[User]
Okay, I need help designing a parametric robotic claw in OpenSCAD. I've been working on a design, but it's a bit messy and I think an AI could do a better job. I'm using the `MCAD` library for the involute gears.

Here's a breakdown of what I need:

**Overall Structure:**

*   The claw should be driven by a servo motor and have a gear system to increase torque and adjust the grip width.
*   The claw will have a base plate to mount to the servo, arms that are driven by gears, and grippers attached to those arms. There will be a cover plate on top.
*   I need to be able to easily adjust several key parameters to customize the claw for different applications.

**Key Parameters (and their ranges):**

*   **`Rot`**: Rotation of the servo in degrees (0-180). This controls the claw opening/closing.
*   **`assembly`**: A selector to switch between showing the assembled claw and showing individual printable parts (0: Assembled, 1: Printable - Gears, 2: Printable - Bottom Plate, 3: Printable - Top Plate, 4: Printable - Arms, 5: Printable - Grippers, 6: Printable - Servo Rotation Mount).
*   **`Gear_Stages`**: Number of gear reduction stages (0: Direct drive, 1: Single reduction, 2: Double reduction).
*   **`show_target`**: Show or hide a target object for reference. (1: Show, 0: Hide).
*   **`target_side`**: Size of the target object (5-200).
*   **`target_translation`**: How far in the x direction from the center the target should be (0-200).
*    **`hide_coverplate`**: Show or hide the cover plate (0:Show, 1:Hide).
*   **`arm_length`**: Length of the claw arms (5-70).
*   **`arm_width`**: Width of the claw arms (5-15).
*   **`arm_thickness`**: Thickness of the arms and gears (2-8).
*   **`grip_angle`**: Angle of the grippers relative to the arms (This one will be hard coded to be 2x the value the user specifies but needs to remain exposed).
*   **`freeArmStay_Offset`**: Distance between gear arms and free arms (10-50).
*   **`hand_length`**: Length of the gripper hands (10-70).
*   **`GripPlate_height`**: Thickness of the gripper plates (10-50).
*    **`Gear_thickness`**: Thickness of the gears (same as arm_thickness)
*   **`Gear_Teeth`**: Number of teeth on the small gears (10 is good).
*   **`Gear_Pitch`**: Gear pitch (400 is good).
*   **`Gear_Play`**: Space between gears (0.2 is good, smaller is tighter).
*   **`Screw_Size`**: Diameter of the screw holes (3).
*   **`Screw_play`**: Extra space for screw holes (0.1).
*   **`plate_thickness`**: Thickness of the base and cover plates (1-5).

**Specific Requirements:**

*   **Gears:** Use the `involute_gears` module from the `MCAD` library to generate the gears, The gear calculations use `circular_pitch`. There should be a small gear at the servo motor, and one or two large gears on the claw arms. These should be parametrically sized to be correct for the gear stages specified.
*   **Arms:** The arms should be simple beams that connect the gears to the grippers.
*   **Grippers:** The grippers should have a simple beam and a flat gripping plate. The grippers should also have a little bit of an offset between the arms and the plates.
*   **Base and Cover Plate:** The base and cover plates should have holes for mounting screws as well as holes for the gears.
*   **Servo Mount:** There needs to be some form of servo motor mount for a micro servo.
*   **Printable Parts:** The printable part options should be easily printable on a standard 3D printer. The print orientation should be optimized for strength and minimal supports.

**Output:**

*   The output should be a single OpenSCAD file.
*   The code should be well-commented and easy to understand.
*   The code should use named modules for each part of the claw (e.g., `gear_arm`, `gripper`, `base_plate`).

Could you help me generate this parametric OpenSCAD file? I would also appreciate an explanation of how the parameters interact with the design once it's made.

[Assistant]
Claw.scad:
```
use <MCAD/involute_gears.scad>

// preview[view:west, tilt:top]

//Rotation of the servo in degrees
Rot = 0;	//[0:180]
//Display Assembled or printable
assembly = 0;//[0:Assembled,1:Printable - Gears,2:Printable - Bottom Plate,3:Printable - Top Plate,4:Printable - Arms,5:Printable - Grippers,6:Printable - Servo Rotation Mount]
//Number of gear stages
Gear_Stages = 1; //[0:Direct,1:Single Reduced,2:Double Reduced]
//Display Sizing Target
show_target = 1;//[1:Show,0:Hide]
//Size of the target object
target_side = 50; //[5:200]

//Move Target Object
target_translation = 110; //[0:200]
//Show Top Plate
hide_coverplate = 1; //[0:Show,1:Hide]

//Length of arms
arm_length = 45;//[5:70]
//Width of arms
arm_width = 8;//[5:15]
//Thickness of arms (and gears)
arm_thickness = 5;//[2:8]

grip_angle = 15*2;
//Offset between gear arms and free arms
freeArmStay_Offset = 32;//[10:50]
// length of gripper hand
hand_length = 30;//[10:70]
//Gripper thickness
GripPlate_height = 15;//[10:50]
Gear_thickness = arm_thickness;
//Number of teeth on the small gears
Gear_Teeth = 10;

Gear_Pitch = 400;
//Space between gears (smaller is tighter)
Gear_Play = 0.2;

Small_Gear_rad = (Gear_Teeth * Gear_Pitch / 180)/2;
Large_Gear_rad = (Gear_Teeth*2 * Gear_Pitch / 180)/2;
//Size of joining holes (PLA filliment can be used)
Screw_Size = 3;
//Fudge factor for joining holes
Screw_play = 0.1;
//Cover plate thickness
plate_thickness = 3;//[1:5]

// Calculated
Screw_Hole = Screw_Size + Screw_play;
Small_Gear_Pos = (Small_Gear_rad+Gear_Play/2);
Arm_Gear_Pos = (Small_Gear_rad*2)*Gear_Stages+Large_Gear_rad+(Gear_Play*(Gear_Stages*2));
grip_offset = arm_length + Arm_Gear_Pos;

$fn=2*20;

gear_pos_small_l1 = [0,(Small_Gear_rad+Gear_Play/2),Gear_thickness];
gear_pos_small_r1 = [0,-(Small_Gear_rad+Gear_Play/2),0];
gear_pos_small_l2 = [0,(Small_Gear_rad+Gear_Play/2)*3,0];
gear_pos_small_r2 = [0,-(Small_Gear_rad+Gear_Play/2)*3,0];
gear_pos_large_r = [0,-Arm_Gear_Pos,0];
gear_pos_large_l = [0,Arm_Gear_Pos,0];

freeArmStay_pos_r = [(freeArmStay_Offset*cos(30)),-grip_offset+((freeArmStay_Offset*sin(30)))+arm_length,0];
freeArmStay_pos_l = [(freeArmStay_Offset*cos(30)),grip_offset-((freeArmStay_Offset*sin(30)))-arm_length,0];

Grip_pos_l = [(arm_length*sin(Rot/2)),grip_offset-(arm_length*(1-cos(Rot/2))),-arm_thickness-0.3];
Grip_pos_r = [(arm_length*sin(Rot/2)),-grip_offset+(arm_length*(1-cos(Rot/2))),-arm_thickness-0.3];

GripPlate_pos_l = [(arm_length*sin(Rot/2))+(freeArmStay_Offset*cos(grip_angle))+(hand_length),grip_offset-(arm_length*(1-cos(Rot/2)))+(freeArmStay_Offset*(-sin(grip_angle))),0];
GripPlate_pos_r = [(arm_length*sin(Rot/2))+(freeArmStay_Offset*cos(grip_angle))+(hand_length),-grip_offset+(arm_length*(1-cos(Rot/2)))+(freeArmStay_Offset*(sin(grip_angle))),0];

if(assembly == 0){
claw_assembled();
}
else{
print_plate();
}
module claw_assembled() {

	if(show_target){translate([target_translation,0,0])cube([target_side,target_side,target_side],true);}

	if (Gear_Stages >= 1){
	translate(gear_pos_small_l1)rotate([0,180,Rot+(90*Gear_Stages+90)])ServoGear();
	translate(gear_pos_small_r1)rotate([0,0,-Rot+(90*Gear_Stages+90)])GearSmallL();
		if (Gear_Stages >= 2){
			translate(gear_pos_small_l2)rotate([0,0,-Rot+(90)])GearSmallL();
			translate(gear_pos_small_r2)rotate([0,0,-Rot])GearSmallL();
		}
	}
	translate(gear_pos_large_l)rotate([0,0,-Rot/2])GearArmL(arm_length);
	translate(gear_pos_large_r)rotate([0,0,Rot/2])GearArmR(arm_length);
	translate(freeArmStay_pos_r)rotate([0,0,Rot/2])FreeArmStayR(arm_length);
	translate(freeArmStay_pos_l)rotate([0,0,-Rot/2])FreeArmStayL(arm_length);
	translate(Grip_pos_l)rotate([0,0,-grip_angle])GripL();
	translate(Grip_pos_r)rotate([0,0,grip_angle])GripR();
	translate(GripPlate_pos_l)rotate([0,0,-90])grip_plate();
	translate(GripPlate_pos_r)rotate([0,0,90])grip_plate();

	if(hide_coverplate == 0){translate([0,0,Gear_thickness+2])cover_plate();}
	translate([0,0,-2])Servo_plate();
	if(Gear_Stages >= 1){
		translate([-Small_Gear_rad*1.5 - 16,0,2])rotate([0,90,0])claw_rotate_plate();
	}
	else{
		translate([-Large_Gear_rad*1.5 - 16,0,2])rotate([0,90,0])claw_rotate_plate();
	}
}

module print_plate() {

	if(assembly == 6){claw_rotate_plate();}
	if(assembly == 5){rotate([0,90,0])grip_plate();}
	if(assembly == 5){
		if(GripPlate_height<((hand_length*0.7)*2)){
			translate([GripPlate_height*1.5,0,0])rotate([0,90,0])grip_plate();
		}
		else{
			translate([0,((hand_length*0.7)*3),0])rotate([0,90,0])grip_plate();
		}

	}

	if(assembly == 2){rotate([0,180,])Servo_plate();}
	if(assembly == 3){cover_plate();}
	if(assembly == 1){
		if (Gear_Stages >= 2){translate([0,-Small_Gear_rad*3.6,0])GearSmallL();	}
		if (Gear_Stages >= 2){translate([0,Small_Gear_rad*3.6,0])rotate([0,0,90])GearSmallL();}
		if (Gear_Stages >= 1){translate([0,Small_Gear_rad*1.2,0])GearSmallL();}
		if (Gear_Stages >= 1){translate([0,-Small_Gear_rad*1.2,0])ServoGear();}
		translate([Small_Gear_rad*1.2 + Large_Gear_rad*1.2,0,0])rotate([0,0,180])GearArmR(arm_length);
		translate([-Small_Gear_rad*1.2 - Large_Gear_rad*1.2,0,0])GearArmL(arm_length);
	}
	if(assembly == 4){
		translate([0,-arm_width*0.7,0])rotate([0,0,90])FreeArmStayL(arm_length);
		translate([0,arm_width*0.7,0])rotate([0,0,-90])FreeArmStayR(arm_length);
		translate([0,arm_width*2,0])rotate([0,0,180])GripR();
		translate([0,-arm_width*2,0])rotate([0,0,180])GripL();
	}
	//translate([4.5,2,-2.4])rotate([0,180,-60])med_servo_holder();
}

module claw_rotate_plate() {

	difference(){
		union() {
			cylinder(r=12.5,h=4);
			translate([0,0,8])cube([7,20,12],true);
		}
		union() {
			translate([0,0,8])cube([8,6,20],true);
			translate([-9,0,-1])cylinder(r=1.5,h=30);
			translate([9,0,-1])cylinder(r=1.5,h=30);
			translate([-15,5,11])rotate([0,90,0])cylinder(r=1.5,h=30);
			translate([-15,-5,11])rotate([0,90,0])cylinder(r=1.5,h=30);
		}
	}
}

module grip_plate() {

	difference(){
		union() {
			translate([8,0,0])cube([4,(hand_length*0.7)*2,GripPlate_height],true);
			beam(8);
		}
		translate([14,0,0])cube([8,20,20],true);
	}

}

module med_servo_holder() {
	union() {
	translate([-14,0,-1.4])cube([3,18,2],true);
	difference(){
			union() {
				cube([45,18,11],true);
				translate([19,0,7])difference(){
					cube([7,18,5],true);
					translate([-1.7,0,-0.5])cube([5,14,3.1],true);
				}
			}
		union(){
			translate([8,0,-6])cylinder(r=4.5,h=12);
			translate([4,0,-6])cylinder(r=3.4,h=12);
			translate([0,-6.5,5])cube([38,1,3],true);
			translate([0,6.5,5])cube([38,1,3],true);
			translate([0,0,3])cube([31,14,11],true);
			translate([-17.5,0,-6])cylinder(r=1.7,h=12);
			translate([17.5,0,-6])cylinder(r=1.7,h=12);
			translate([0,0,-4.4])cube([46,19,4],true);
		}
	}
}
}

module Servo_plate() {
	difference(){
		union() {
			empty_plate();
			if (Gear_Stages >= 1){
				translate([-Small_Gear_rad*1.5,0,0])difference(){
					cube([20,20,plate_thickness],true);
					union() {
						translate([-5,5,-4])cylinder(r=Screw_Hole/2,h=15);
						translate([-5,-5,-4])cylinder(r=Screw_Hole/2,h=15);
					}
				}
			}
			else {
				translate([-Large_Gear_rad*1.5,0,0])difference(){
					cube([20,20,plate_thickness],true);
					union() {
						translate([-5,5,-4])cylinder(r=Screw_Hole/2,h=15);
						translate([-5,-5,-4])cylinder(r=Screw_Hole/2,h=15);
					}
				}
			}
			translate([4.5,2,-3.9])rotate([0,180,-60])med_servo_holder();
		}
		union() {
			plate_holes();
			translate(gear_pos_small_r1+[0,0,-5-plate_thickness/2])rotate([0,0,-60])cube([6,6,10],true);
		}
	}
}

module cover_plate() {
	difference(){
		union() {
			empty_plate();
			if (Gear_Stages >= 1){
				translate([-Small_Gear_rad*1.5,0,0])difference(){
					cube([20,20,plate_thickness],true);
					union() {
						translate([-5,5,-4])cylinder(r=Screw_Hole/2,h=15);
						translate([-5,-5,-4])cylinder(r=Screw_Hole/2,h=15);
					}
				}
			}
			else {
				translate([-Large_Gear_rad*1.5,0,0])difference(){
					cube([20,20,plate_thickness],true);
					union() {
						translate([-5,5,-4])cylinder(r=Screw_Hole/2,h=15);
						translate([-5,-5,-4])cylinder(r=Screw_Hole/2,h=15);
					}
				}
			}
		}
		plate_holes();
	}
}

module plate_holes() {
	union() {
			if (Gear_Stages >= 1){
				translate(gear_pos_small_l1+[0,0,-10])cylinder(r=6,h=9);
				translate(gear_pos_small_r1+[0,0,-10])cylinder(r=Screw_Hole/2,h=15);
				if (Gear_Stages >= 2){
					translate(gear_pos_small_l2+[0,0,-10])cylinder(r=Screw_Hole/2,h=15);
					translate(gear_pos_small_r2+[0,0,-10])cylinder(r=Screw_Hole/2,h=15);
				}
			}
			translate(gear_pos_large_r+[0,0,-10])cylinder(r=Screw_Hole/2,h=15);
			translate(gear_pos_large_l+[0,0,-10])cylinder(r=Screw_Hole/2,h=15);
			translate(freeArmStay_pos_r + [0,0,-10])cylinder(r=Screw_Hole/2,h=15);
			translate(freeArmStay_pos_l + [0,0,-10])cylinder(r=Screw_Hole/2,h=15);
		}
}

module empty_plate() {

	if (Gear_Stages >= 1){
		translate([0,0,-plate_thickness/2])polyhedron(
		points = [
			gear_pos_large_r + [-0,-5,0],
			gear_pos_large_l + [-0,5,0],
			gear_pos_large_r + [-Small_Gear_rad*1.5,-0,0],
			gear_pos_large_l + [-Small_Gear_rad*1.5,0,0],
			freeArmStay_pos_r + [5,-5,0],
			freeArmStay_pos_l + [5,5,0],
			gear_pos_large_r + [-0,-5,plate_thickness],
			gear_pos_large_l + [-0,5,plate_thickness],
			gear_pos_large_r + [-Small_Gear_rad*1.5,0,plate_thickness],
			gear_pos_large_l + [-Small_Gear_rad*1.5,0,plate_thickness],
			freeArmStay_pos_r + [5,-5,plate_thickness],
			freeArmStay_pos_l + [5,5,plate_thickness]
		],
		triangles = [
			[4,5,1,3,2,0],
			[10,6,8,9,7,11],
			[3,9,8,2],
			[0,2,8,6],
			[7,9,3,1],
			[11,7,1,5],
			[4,0,6,10],
			[5,4,10,11]
		]
		);
	}
	else {
		translate([0,0,-plate_thickness/2])polyhedron(
		points = [
			gear_pos_large_r + [-0,-Large_Gear_rad*0.5,0],
			gear_pos_large_l + [-0,Large_Gear_rad*0.5,0],
			gear_pos_large_r + [-Large_Gear_rad*1.5,-0,0],
			gear_pos_large_l + [-Large_Gear_rad*1.5,0,0],
			freeArmStay_pos_r + [5,-5,0],
			freeArmStay_pos_l + [5,5,0],
			gear_pos_large_r + [-0,-Large_Gear_rad*0.5,plate_thickness],
			gear_pos_large_l + [-0,Large_Gear_rad*0.5,plate_thickness],
			gear_pos_large_r + [-Large_Gear_rad*1.5,0,plate_thickness],
			gear_pos_large_l + [-Large_Gear_rad*1.5,0,plate_thickness],
			freeArmStay_pos_r + [5,-5,plate_thickness],
			freeArmStay_pos_l + [5,5,plate_thickness]
		],
		triangles = [
			[4,5,1,3,2,0],
			[10,6,8,9,7,11],
			[3,9,8,2],
			[0,2,8,6],
			[7,9,3,1],
			[11,7,1,5],
			[4,0,6,10],
			[5,4,10,11]
		]
		);
	}
}

module Servo_Mount_Holes() {
	union() {
		translate([0,0,0])cylinder(r=6,h=9);
		translate([0,0,0])cylinder(r=3,h=11);
		translate([26.5,0,-4.3])cylinder(r=1.55,h=10);
		translate([26.5,0,6],$fn=6)cylinder(r=3,h=3);
	}
}

module beam(l=20) {
	translate([0,-arm_width/2,0])difference(){
			union() {
				cube([l,arm_width,arm_thickness]);
				translate([l,arm_width/2,0])cylinder(r=arm_width/2,h=arm_thickness);
				translate([0,arm_width/2,0])cylinder(r=arm_width/2,h=arm_thickness);
			}
			union() {
				translate([l,arm_width/2,-1])cylinder(r=Screw_Hole/2,h=arm_thickness+2);
				translate([0,arm_width/2,-1])cylinder(r=Screw_Hole/2,h=arm_thickness+2);
			}
		}
}

module GripR() {
	beam(freeArmStay_Offset);
	translate([freeArmStay_Offset,0,0])rotate([0,0,-grip_angle])beam(hand_length);
}

module GripL() {
	beam(freeArmStay_Offset);
	translate([freeArmStay_Offset,0,0])rotate([0,0,grip_angle])beam(hand_length);
}

module FreeArmStayR(l=38) {
	rotate([0,0,-90])beam(l);
}

module FreeArmStayL(l=38) {
	rotate([0,0,90])beam(l);
}

module GearSmallL() {
	rotate([0,0,90])gear (number_of_teeth=Gear_Teeth,
					circular_pitch=Gear_Pitch,
					gear_thickness = Gear_thickness,
					rim_thickness = Gear_thickness,
					hub_thickness = Gear_thickness,
					hub_diameter = 0,
					bore_diameter = Screw_Hole,
					circles=0);
}

module GearArmR(l=38) {
	rotate([0,0,-90])difference(){
		union() {
			rotate([0,0,45])gear (number_of_teeth=2*Gear_Teeth,
								circular_pitch=Gear_Pitch,
								gear_thickness = Gear_thickness,
								rim_thickness = Gear_thickness,
								hub_thickness = Gear_thickness,
								hub_diameter = 0,
								bore_diameter = Screw_Hole,
								circles=0);

			beam(l);
		}
	}
}

module GearArmL(l=38) {
	rotate([0,0,90])difference(){
		union() {
			gear (number_of_teeth=2*Gear_Teeth,
								circular_pitch=Gear_Pitch,
								gear_thickness = Gear_thickness,
								rim_thickness = Gear_thickness,
								hub_thickness = Gear_thickness,
								hub_diameter = 0,
								bore_diameter = Screw_Hole,
								circles=0);

			beam(l);
		}
		if (Gear_Stages == 0){
			translate([0,0,1.5])cylinder(r=2.9,h=Gear_thickness);
		}
	}
}

module ServoGear() {

difference(){
	gear (number_of_teeth=Gear_Teeth,
					circular_pitch=Gear_Pitch,
					gear_thickness = 0,
					rim_thickness = Gear_thickness,
					hub_thickness = Gear_thickness+4,
					hub_diameter = 9,
					bore_diameter = Screw_Hole,
					circles=0);

	translate([0,0,1.5])cylinder(r=3.1,h=Gear_thickness+4);
}

}
```


[User]
Okay, I need help creating a more robust and flexible parametric motor case generator in OpenSCAD. I've already got a basic version working, but it has a few limitations, and I think it could benefit from being more comprehensive and user-friendly.

Here's what my current script does:

*   It takes parameters for the motor diameter (`dm`), case thickness (`th`), motor height (`hc`), height to the ends of the motor (`he`), diameter of those ends (`de`), the distance between those ends (`dbe`), the length of those ends (`le`), and the distance to the ends (`dte`).
*   It generates a basic cylindrical case with an internal void for the motor, and two cylindrical protrusions for the motor's end features.
*   It uses a simple conditional to determine if the end cylinders should be cut shorter if they would protrude into the case.
*   It is based on difference between cylinders.

Here's what I'd like this new script to do:

1.  **More Flexible End Features:** My current design only handles cylindrical end features on the motor. I need to be able to handle different shapes such as rectangular prongs or even mounting tabs on the sides. Ideally, the user should be able to define the shape (cube, cylinder), size, and position of these features through parameters. Perhaps using `linear_extrude` on a user specified polygon or circle, and translation parameters? I should be able to define multiple end features on a motor.

2.  **Hole & Screw Placement:** The most important addition I need is the ability to add mounting screw holes at specified locations on the case. These should also be parametric, allowing the user to specify the number of holes, their diameter, and their position (perhaps using polar coordinates or relative positioning from a specified origin). I'd like to be able to specify the screw head clearance too. I think being able to define them as a vector of tuples (or whatever) might be best.

3.  **Alignment Features:** It would be good to be able to add alignment features, like small pegs or notches on the case so that it could be attached to something precisely. These would also need to be configurable with parameters. The user should be able to choose the shape, size, and position of any number of these alignment features.

4.  **Optional Internal Supports:** For very long or narrow motor cases, internal support structures might be needed to increase rigidity. Being able to add internal ribs or other supporting structures that are parametric and automatically generated would be fantastic. A simple radial structure would probably suffice.

5.  **Clearance and Tolerances:** I need a way to specify some general clearance parameters so that the parts fit nicely without being too tight or too loose. Also, the screw hole should have a clearance as well.

6.  **User-Friendly Parameter Input:** Perhaps a way to use comments to create more self-explanatory parameter inputs?

7.  **Library Use:** I'd also like the code to be well-organized. It might be beneficial to use a library for some of these tasks, such as the `BOSL2` library, if there are helper functions that can streamline the process.

Essentially, I want a robust motor case generator that can handle a wide variety of motors and mounting scenarios. I'd love it if the new code is well-commented and easy to understand for future modifications. Could you generate the OpenSCAD code for this?

I'm not too familiar with all of the functions in BOSL2, so be sure to explain the usage of any included functions.

[Assistant]
Motor.scad:
```
// This is a parametric case maker for a motor

//Example1

// to make a custom case, replace the parameters with your own

//examplemotor1
dm = 24.5; // Diameter of motor
th = 2; // Thickness of case
hc = 13; // Height of motor
he =  dm/2; // Height to ends
de = 2; // Diameter of ends
dbe = 15.75; // Distance between ends
le = 2.5; // Length of ends
dte = le/2; // Distance to ends

//Example2

//to use, get rid of "/*" and "*/"

/*//examplemotor2
dm = 18; // Diameter of motor
th = 2; // Thickness of case
hc = 28; // Height of motor
he =  19; // Height to ends
de = 4; // Diameter of ends
dbe = 12.5; // Distance between ends
le = 5; // Length of ends
dte = 7; // Distance to ends*/

//program
if (le-dte >0)
{
difference() {
cylinder(r = (dm/2+th), h = (hc+th));
cylinder(r = (dm/2), h = hc);
translate([dm/2-he,dbe/2,hc-dte/2])
cylinder(r = (de/2)+th, h = le+2 * th, center = true);
translate([dm/2-he,-dbe/2,hc-dte/2])
cylinder(r = (de/2)+th, h = le+2 * th, center = true);
}
}
else
{
difference() {
cylinder(r = (dm/2+th), h = (hc+th));
cylinder(r = (dm/2), h = hc);
translate([dm/2-he,dbe/2,hc-dte/2])
cylinder(r = (de/2)+th, h = le, center = true);
translate([dm/2-he,-dbe/2,hc-dte/2])
cylinder(r = (de/2)+th, h = le, center = true);
}
}
```


[User]
Okay, I'd like to design a flexible chain that I can 3D print without needing support material. I've found an existing OpenSCAD script that does most of what I want, but I'd like something a bit more customizable and easier to tweak.

Here's what I'm looking for:

**Core Functionality (Based on Existing Script):**

*   **Parametric Link Design:** The chain is built from interconnected links with rounded ends. The links should be generated parametrically based on a few key variables.
*   **Three Chain Types:** I'd like to be able to choose from three chain configurations:
    *   **Straight Chain:** A simple linear chain.
    *   **Circular Chain:** A closed loop chain. The user should be able to specify the radius of the loop.
    *   **Spiral Chain:** A chain that spirals outwards, similar to an Archimedes spiral. The user should be able to specify the initial radius and the pitch (rate of expansion).
*   **No Support Required:** The design of the link should allow for printing without support structures. I've had success with the linked script for this.

**Desired Customization Parameters:**

*   **`links`**:  The number of links in the chain. For the circular chain, it'll need to be an even number.
*   **`l`**: The overall length of a single link.
*   **`d`**: The width of a single link.  This width may need to be slightly larger for the circular and spiral chains to make space for the curvature, but should be a single parameter.
*   **`t`**: The thickness (diameter of cross-section) of the link's material.
*   **`chain_type`**: A string parameter to choose which of the three types to generate ("straight", "circular", "spiral").
*   **`radius`**: (For "circular" `chain_type` only) The radius of the circular chain.
*   **`r0`**: (For "spiral" `chain_type` only) The initial radius of the spiral.
*   **`pitch`**: (For "spiral" `chain_type` only) The rate of expansion (pitch) of the spiral.
*   **`link_angle`**: Parameter specifying the angle between each chain link. 60 degrees is a good starting point for all types, but I would like the ability to modify this in particular for the circular chain, where it may need to change to accommodate a specific number of links and a radius.

**Additional Request**

*   I don't have a lot of experience with advanced math functions in OpenSCAD, so I would need all the calculation functions (for archimedes spiral, angles, etc) built into the script. I don't think I'll need to use any external libraries for this.
*   I would like the option to also control the angle of the connection between the link elements. For example, maybe the links don't rotate along the width, but instead rotate along the length of the link.
*   The script should be well commented and easy to understand.
*   Please generate a single OpenSCAD file.

Can you provide an OpenSCAD script that does this?

[Assistant]
chain.scad:
```
/**************
Chain generator
(http://www.thingiverse.com/thing:28405)

Author: Stefan Langemark

Generates open or closed chains with configurable
dimensions. Print without support.

Open chains (two ends):
straight_chain()
spiral_chain()

Closed chains (no end):
circular_chain()

Common parameters:
l - length of link
d - width of link
t - thickness of material
links - number of links in chain
The length of the chain when stretched is links*(l-2*t)

The spiral and circular chains need a bit wider chains
than the straight chain to make room for the curvature.

***************/

/**************
 Select output here!
***************/

// Shape of chain
type = "straight"; // [straight,circular,spiral]

// Number of links. Needs to be an even number for circular type!
links = 10;

// Length of link
l = 22;

// Width of link (increase to 15 for circular or spiral type)
d = 12;

// Diameter of cross section
t = 3.5;

// Initial radius for spiral type
r0 = 20;

// Increase of radius per turn for spiral type
pitch = 12;

if (type == "straight") straight_chain(links, l,d,t);
if (type == "circular") circular_chain(links, l,d,t);
if (type == "spiral") spiral_chain(links, l,d,t,r0,pitch);

/*
Open chain in a spiral.
Additional parameters:
r0 - initial radius (mm).
pitch - increase of radius per turn (mm/turn).
*/
module spiral_chain(links=30,l=22,d=15,t=3.5,r0=20,pitch=12)
{
	spacing=l/2+1;
	for (i=[0:links-1])
	assign(angle = inv_arch_len(spacing*i,r0,pitch),
		angle2 = inv_arch_len(spacing*(i+1),r0,pitch))
	assign(p = arch_spiral(angle,pitch),
		p2 = arch_spiral(angle2,pitch))
	{
		translate(p)
		rotate([0,0,atan2(p2[1]-p[1],p2[0]-p[0])])
		translate([spacing/2,0,0])
		rotate([60+60*(i%2),0,0])
		link(l,d,t);
	}
}

// Straight chain segment
module straight_chain(links=5, l = 22, d = 12, t = 3.5)
{
	spacing=l/2+.5;
	for (i=[0:links-1]) {
		translate([i*spacing,0,0])rotate([60+60*(i%2),0,0])link(l,d,t);
	}
}

// Closed chain in a circle
module circular_chain(links=14, l = 22, d = 15, t = 3.5)
{
	a = 360/links;
	spacing=l/2+1; // tweak this to make chains with few links
	r=spacing/2/tan(a/2);
	echo("radius",r);
	for (i=[0:links-1]) {
		rotate([0,0,i*a])translate([0,-r,0])rotate([60+60*(i%2),0,0])link(l,d,t);
	}
}

// Single chain link. Centered, with l,d,t in axes x,y,z, respectively.
module link(l,d,t)
{
	union() {
	for (a=[0:7])
	{
		assign(
			off1 = (l-d)/2*((a-.5>2&&a-.5<6)?-1:1),
			off2 = (l-d)/2*((a+.5>2&&a+.5<6)?-1:1))
		{
			intersection() {
				translate([0,0,-t/2])
				pie((a-.5)*360/8,
					(a+.5)*360/8,l,t,
					[off1,0],[off2,0]);
				translate([(off1+off2)/2,0,0])
				rotate([0,0,a*360/8])
				rotate([-90,0,0])
				translate([(d-t)/2,0,-l/2])
				cylinder($fn=6,r=t/2,h=l);
			}
		}
	}
}
}

function pol(r,a) = [r*cos(a),r*sin(a)];
module pie(a1,a2,r,h,o1,o2)
{
	if (o1==o2) {
	linear_extrude(height=h)
		polygon([o1,o1+pol(r,a1),o1+pol(r,a2)]);
	} else {
	linear_extrude(height=h)
		polygon([o1,o1+pol(r,a1),o2+pol(r,a2),o2]);
	}
}

// Approximate angle of archimedes spiral of length len (mm) from radius r0, given pitch a (mm/turn).
function inv_arch_len(len,r0,a) = 180/3.1416*sqrt(len*2/(a/2/3.1416)+(r0*2*3.1416/a)*(r0*2*3.1416/a));

// Point on archimedes spiral at angle given pitch a (mm/turn).
function arch_spiral(angle,a) = [a*angle/360*cos(angle),a*angle/360*sin(angle),0];

```


[User]
Okay, I'd like to design a parametric servo arm using OpenSCAD. I've seen a previous design that looks promising, but I want a more generalized version and some additional features.

Here's what I need:

**Core Functionality:**

*   **Parametric Servo Spline:** I need to be able to define the servo spline parameters for different servo types. This should include:
    *   Head external diameter
    *   Head height
    *   Head thickness
    *   Head screw diameter
    *   Tooth count
    *   Tooth height
    *   Tooth length
    *   Tooth width
    I need a way to create presets for common servo types (like Futaba 3F, etc.) but also be able to define my own.

*   **Arm Creation:**
    *   The arm should be connected to the servo head, and I want to be able to specify the number of arms.
    *   The arms should be equidistant from one another, so if I say 4 arms, they should be at 90-degree intervals around the servo spline.
    *   I need to control the overall length of the arms (distance from the center of the spline to the last screw hole on the arm).
    *   Each arm needs to have screw holes, and I need to be able to control how many holes there are and the spacing of those holes along the arm, as well as the screw diameter.
    *   The arms should have a customizable thickness.
    *   There should be an option for a support structure on each arm for added strength. The support should be optional.

*   **Clearance:** There needs to be a clearance parameter between the servo head and the servo arm to account for printing tolerances.

*   **Units:** I want everything to be in millimeters (mm).

**Specific Feature Requests (that go beyond the provided example):**

*   **Arm Profile Customization:** I'd like some flexibility in the shape of the arms. Specifically, I'd like to be able to choose between a rectangular, tapered (wider at the base than the end), and perhaps a triangular profile for the arm.
*   **Hole Placement Flexibility**:  Instead of fixed spacing of the holes, I need the ability to specify the location of each hole individually, as an array of distances from the servo spline center. I would still like the option of a uniform count and spacing.
*   **Filleting/Chamfering:** It would be great to have an option to add fillets or chamfers to the edges of the servo head and the arm for aesthetic reasons and to reduce stress concentrations.
*   **Customizable Arm Width:** I need to be able to control the arm width.
*  **Optional center support:** There should be an option to have a central support hub (similar to the servo head) between all the arms connecting them for additional support. This also needs to be optional and have customizable diameter and thickness.

**Libraries**
I don't intend to use any external libraries, just native OpenSCAD functions.

**Output:**

I need the output to be an OpenSCAD file (.scad) that incorporates all these parametric features. I want it to be easy to modify the parameters at the top of the file to generate different servo arms.

[Assistant]
servo_arm.scad:
```
/**
 *  Parametric servo arm generator for OpenScad
 *  Générateur de palonnier de servo pour OpenScad
 *
 *  Copyright (c) 2012 Charles Rincheval.  All rights reserved.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *  Last update :
 *  https://github.com/hugokernel/OpenSCAD_ServoArms
 *
 *  http://www.digitalspirit.org/
 */

arm_length = 20;

arm_count = 4; // [1,2,3,4,5,6,7,8]

//  Clear between arm head and servo head (PLA: 0.3, ABS 0.2)
SERVO_HEAD_CLEAR = 0.2; // [0.2,0.3,0.4,0.5]

$fn = 40 / 1;

/**
 *  Head / Tooth parameters
 *  Futaba 3F Standard Spline
 *  http://www.servocity.com/html/futaba_servo_splines.html
 *
 *  First array (head related) :
 *  0. Head external diameter
 *  1. Head heigth
 *  2. Head thickness
 *  3. Head screw diameter
 *
 *  Second array (tooth related) :
 *  0. Tooth count
 *  1. Tooth height
 *  2. Tooth length
 *  3. Tooth width
 */
FUTABA_3F_SPLINE = [
    [5.92, 4, 1.1, 2.5],
    [25, 0.3, 0.7, 0.1]
];

module servo_futaba_3f(length, count) {
    servo_arm(FUTABA_3F_SPLINE, [length, count]);
}

/**
 *  If you want to support a new servo, juste add a new spline definition array
 *  and a module named like servo_XXX_YYY where XXX is servo brand and YYY is the
 *  connection type (3f) or the servo type (s3003)
 */

module servo_standard(length, count) {
    servo_futaba_3f(length, count);
}

/**
 *  Tooth
 *
 *    |<-w->|
 *    |_____|___
 *    /     \  ^h
 *  _/       \_v
 *   |<--l-->|
 *
 *  - tooth length (l)
 *  - tooth width (w)
 *  - tooth height (h)
 *  - height
 *
 */
module servo_head_tooth(length, width, height, head_height) {
    linear_extrude(height = head_height) {
        polygon([[-length / 2, 0], [-width / 2, height], [width / 2, height], [length / 2,0]]);
    }
}

/**
 *  Servo head
 */
module servo_head(params, clear = SERVO_HEAD_CLEAR) {

    head = params[0];
    tooth = params[1];

    head_diameter = head[0];
    head_heigth = head[1];

    tooth_count = tooth[0];
    tooth_height = tooth[1];
    tooth_length = tooth[2];
    tooth_width = tooth[3];

    % cylinder(r = head_diameter / 2, h = head_heigth + 1);

    cylinder(r = head_diameter / 2 - tooth_height + 0.03 + clear, h = head_heigth);

    for (i = [0 : tooth_count]) {
        rotate([0, 0, i * (360 / tooth_count)]) {
            translate([0, head_diameter / 2 - tooth_height + clear, 0]) {
                servo_head_tooth(tooth_length, tooth_width, tooth_height, head_heigth);
            }
        }
    }
}

/**
 *  Servo hold
 *  - Head / Tooth parameters
 *  - Arms params (length and count)
 */
module servo_arm(params, arms) {

    head = params[0];
    tooth = params[1];

    head_diameter = head[0];
    head_heigth = head[1];
    head_thickness = head[2];
    head_screw_diameter = head[3];

    tooth_length = tooth[2];
    tooth_width = tooth[3];

    arm_length = arms[0];
    arm_count = arms[1];

    /**
     *  Servo arm
     *  - length is from center to last hole
     */
    module arm(tooth_length, tooth_width, head_height, head_heigth, hole_count = 1) {

        arm_screw_diameter = 2;

        difference() {
            union() {
                cylinder(r = tooth_width / 2, h = head_heigth);

                linear_extrude(height = head_heigth) {
                    polygon([
                        [-tooth_width / 2, 0], [-tooth_width / 3, tooth_length],
                        [tooth_width / 3, tooth_length], [tooth_width / 2, 0]
                    ]);
                }

                translate([0, tooth_length, 0]) {
                    cylinder(r = tooth_width / 3, h = head_heigth);
                }

                if (tooth_length >= 12) {
                    translate([-head_heigth / 2 + 2, 3.8, -4]) {
                        rotate([90, 0, 0]) {
                            rotate([0, -90, 0]) {
                                linear_extrude(height = head_heigth) {
                                    polygon([
                                        [-tooth_length / 1.7, 4], [0, 4], [0, - head_height + 5],
                                        [-2, - head_height + 5]
                                    ]);
                                }
                            }
                        }
                    }
                }
            }

            // Hole
            for (i = [0 : hole_count - 1]) {
                //translate([0, length - (length / hole_count * i), -1]) {
                translate([0, tooth_length - (4 * i), -1]) {
                    cylinder(r = arm_screw_diameter / 2, h = 10);
                }
            }

            cylinder(r = head_screw_diameter / 2, h = 10);
        }
    }

    difference() {
        translate([0, 0, 0.1]) {
            cylinder(r = head_diameter / 2 + head_thickness, h = head_heigth + 1);
        }

        cylinder(r = head_screw_diameter / 2, h = 10);

        servo_head(params);
    }

    arm_thickness = head_thickness;

    // Arm
    translate([0, 0, head_heigth]) {
        for (i = [0 : arm_count - 1]) {
            rotate([0, 0, i * (360 / arm_count)]) {
                arm(arm_length, head_diameter + arm_thickness * 2, head_heigth, 2);
            }
        }
    }
}

module demo() {
    rotate([0, 180, 0])
        servo_standard(arm_length, arm_count);
}

demo();

```


[User]
Okay, I've got a need for a specific kind of filament holder for my 3D printer, and I think a parametric OpenSCAD design is the best approach. I've been using a simple cylinder design, but I'd like to improve it to be more flexible.

My current design, which I've attached as `holder-cylinder.scad`, is a basic hollow cylinder. The parameters are mostly hardcoded, which is limiting. It's intended to slide onto a horizontal rod, like those found in retort stands, to hold a filament spool. However, it's also useful for other types of filament holders as a modular component.

Here’s what I’d like the improved version to be able to do:

**Core Requirements:**

1.  **Hollow Cylinder Shape:**  The design is still based on a hollow cylinder.
2.  **Parametric Dimensions:** I need to be able to control the following parameters, all using variables:
    *   `hole_diameter`: The diameter of the hole that slides onto the bar or another component.
    *   `extraspace_hole`: An additional clearance value added to `hole_diameter`. This will ensure a smooth slide.
    *   `cylinder_diameter`: The outer diameter of the cylinder, which often matches the hole diameter of the filament spool.
    *   `extraspace_diameter`: A value subtracted from `cylinder_diameter` to account for tolerance and friction on the outer surface.
    *   `length`: The length of the cylinder.
3.  **Centering:** The cylinder needs to be centered along its Z-axis.
4.  **High Resolution:** I'd like to use `$fn=100` for all cylinder generations in order to generate a smoother, more accurate curve.

**Additional Considerations/Features:**

*   **Clear Variable Comments:** Please add comments for all parameters describing the units (preferably mm) and their purpose.
*   **Reasonable Defaults:**  Provide reasonable default values for all variables, perhaps based on the ones I'm using currently in my attached file.
*   **Retort Stand Use:** The design should remain usable with a typical 12mm retort stand horizontal bar, but allow for easy alteration.  The idea is to make it compatible with the various filament spool hole sizes (around 31-52 mm diameter).
*   **Modularity:** The main goal is to make this a flexible component, so all parameters have to be adjustable and well-commented.

**Libraries:**

I don't think I need any external libraries for this, just the basic OpenSCAD language features.

**Output:**

I expect a single OpenSCAD file with all of these features incorporated and good commenting.

In summary, I want a reusable, well-commented, and flexible hollow cylinder that I can use for various filament holding applications, which can be tuned for different spooling setups. Thanks for your help!

[Assistant]
holder-cylinder.scad:
```
/* Cylinder with a hole

To slide onto a horizontal bar of a retort stand (aka "chemistry"
stand) so that the filament roll will turn more easily.  You also can
use this to augment various filament holders and stands made from
filament.

Made by Daniel K. Schneider, TECFA, University of Geneva, August 2012, revised Feb 2016
Licence: Freeware

A hollow cylinder is defined by 5 parameters. It's length, the
diameter of the hole, the outside diameter, extra space added to the
hole diameter and extraspace substracted from the outer diameter.

Measure the diameter of the bar (typically 12mm for a retort stand)
and of the holes of your filament rools.  Use these measures as such,
but you can ajust "extraspace_diameter = 0.25;" and "extra_space" inner.

Adapt parameters if needed.

Hole diameter is 1.2 for a typical retort stand

Filament roll hole diameters seem to vary from 19 to 74 mm. Frequent
ones are 31mm, 39mm and 52mm. Outersize diameter ranges from 12.5cm
(e.g. Taulman T-glase) to 30cm. Typical outer width (length of the
cylinder to print) is from 6cm to 12.5cm. Below the ones that I
printed.

// cylinder_diameter = 31.6; //
// cylinder_diameter = 38.3; //
// cylinder_diameter = 50.9; //

Adjust the length. Add extraspace, e.g. 4cm.

*/

// Diameter of the hole
hole_diameter = 17; //

// Extra inner space added to hole diameter
extraspace_hole = 1;

// Diameter of the cylinder (hole of filament roll)
cylinder_diameter = 38.3;

// Outer extra space subtracted from diameter
extraspace_diameter = 0.2;

// Cylinder length
length = 120;

translate ([0,0,length/2]) {
  difference() {
    cylinder (h = length, r=cylinder_diameter / 2 - extraspace_diameter, center = true, $fn=100);
    # cylinder (h = length+2, r=hole_diameter / 2 + extraspace_hole, center = true, $fn=100);
  }
}

```


[User]
Okay, I need a parametric design for a cell phone battery holder, something that will keep a spare battery from shorting out in my bag.

Here's what I need:

**Functionality:**

*   The design should be a rectangular case with a cavity inside for the battery.
*   The case needs to have a certain wall thickness around the battery.
*   The corners on the open face of the case should be radiused/rounded for a more finished look and to make it easier to slide a battery into the case.

**Parameters (these need to be easily adjustable in the code):**

*   `height`: The internal height of the battery cavity, in millimeters.
*   `width`: The internal width of the battery cavity, in millimeters.
*   `depth`: The internal depth of the battery cavity, in millimeters.
*   `singleWallWidth`: The width of a single wall layer, in millimeters (this is based on my 3D printer's nozzle size).
*   `thickness`: The desired number of wall layers.
*   `clearence`: An extra amount of space added to the dimensions to make it easier to insert and remove the battery, in millimeters.

**Specific Design Requirements:**

*   The corners of the opening should be circular with the same radius as the case wall thickness (that is, total thickness).
*   The design should use `difference()` to cut out the battery cavity, and create the rounded corners.
*   I want the code to be parametric.
*   The case should be centered on the origin.

**OpenSCAD Libraries:**

*   I'd prefer to keep this simple and not rely on any external libraries like MCAD, BOSL, etc. so that it's as simple to use for a variety of users as possible.

Could you generate the OpenSCAD code for this battery case? Thanks!

[Assistant]
BatteryHolder.scad:
```
/*
Parametric Cell Phone Battery holder.

Case to hold a spare battery without fear of shorting it out.

Created by Mike Creuzer - Mike@Creuzer.com - 20120816
*/

// Battery dimensions in mm
// Internal height
height = 65;
// Internal Width
width  = 44;
// Internal narrow bit
depth  = 5.4;

// Print Settings in mm
// Looking at the gcode of a sliced file often times tells you this at the top of the file
singleWallWidth = .49;
// Number of walls you want
thickness          = 2;
// how much added 'slop' you want so the case is easier to use.
clearence          = .25;

difference()
{
	cube(size = [width + 2*thickness*singleWallWidth + clearence, depth + 2*thickness*singleWallWidth + clearence, height + thickness*singleWallWidth], center=true);

	translate([0,0,2*thickness*singleWallWidth + clearence]) cube(size = [width,depth, height], center=true);
	translate([.5*(width + 2*thickness*singleWallWidth + clearence),0,.5 * (height + 2*thickness*singleWallWidth + clearence)]) rotate([90,0,0]) cylinder(r = depth + 2*thickness*singleWallWidth, h=depth + 2*thickness*singleWallWidth + clearence, center=true);
	translate([-.5*(width + 2*thickness*singleWallWidth + clearence),0,.5 * (height + 2*thickness*singleWallWidth + clearence)]) rotate([90,0,0]) cylinder(r = depth + 2*thickness*singleWallWidth, h=depth + 2*thickness*singleWallWidth + clearence, center=true);

}

```


[User]
Okay, I need a parametric OpenSCAD design for a cocktail stick, but I want it to be a bit more sophisticated than the simple one I have.  My current design is okay, but it's not very customizable and the ornament is really just a simple ring.

Here's what I'm looking for:

**General Structure:**
*   The basic stick should be a round cylinder with a pointed end (a cone).
*   I need to be able to control the overall length of the stick, the length of the cone section, and the diameter of the cylindrical part.
*   The ornament needs to be more interesting than just a ring. I'd like it to be a separate, customizable element at the end of the stick.

**Specific Features:**
1.  **Parametric Cone:**
    *   I need parameters for the *length* of the cone.
    *   The cone base should match the diameter of the cylindrical section.
    *  The cone should terminate at a point.
2.  **Parametric Cylinder:**
    *   Parameter for the diameter.
    *   The length should be automatically calculated based on total stick length and the cone length.
3.  **Enhanced Ornament:**
    *   Instead of a simple ring, I'd like the ornament to be a sphere, a torus, or a more complex shape like a star, heart, or a simple stylized animal shape.
    *   I need parameters for the *size* (e.g., radius or overall bounding box size) and *thickness* of the ornament, as well as a *selection* for ornament type from a small set of options (sphere, torus, star, heart).
    *   The ornament should be attached to the end of the stick.
4. **Fine Control Over Facet Settings:**
  *   I need to be able to separately control the `$fs` value for the stick and the ornament so that I can have high quality ornaments without generating an excessive amount of facets for the long cylindrical part.
5. **Library Use:**
    *   I think the BOSL2 library could be helpful here, particularly for creating the more complex ornament shapes, if it makes sense.  If a more appropriate library exists for complex shapes, please use that instead.

**Parameters Needed:**

*   `total_length`: Total length of the cocktail stick.
*   `cone_length`: Length of the cone section at the pointy end.
*   `stick_diameter`: Diameter of the cylindrical part of the stick.
*   `ornament_type`: Selection between "sphere", "torus", "star", "heart".
*   `ornament_size`: Overall size of the ornament.
*   `ornament_thickness`: Thickness of the ornament.
*   `stick_fs`:  $fs for the stick.
*   `ornament_fs`: $fs for the ornament.

**Output:**
I'd like a single `.scad` file with all the code included.  It should be well commented and easy to understand. The design should be centered at the origin, so I don't have to worry about relative positioning.

Please let me know if you have any questions, or if this isn't clear enough.

[Assistant]
cocktail_stick.scad:
```
//
// Straight cocktail stick with round, pointed stick
//
// The "ornament" is just a ring
//
// by Egil Kvaleberg
//

//*****************************************************************************
// Adjustables

// length of stick
total_length = 100;

// length of cone section
cone_length = 5;

// diameter of stick
stick_diameter = 3.2;

// size of ornament
ornament_size = 20;

// thickness of ornament
ornament_thickness = 2;

stick_fs = 1*0.1;
ornament_fs = 1*0.5;

//*****************************************************************************
// Derived

stick_radius = stick_diameter / 2;
stick_length = total_length - cone_length;

//*****************************************************************************
// View and printing

view();

//*****************************************************************************
//

module cone()
{
    rotate([0, 90, 0]) cylinder(r1 = 0, r2 = stick_radius, h = cone_length, $fs = stick_fs);
}

module stick()
{
    translate([cone_length, 0, 0]) rotate([0, 90, 0]) cylinder(r = stick_radius, h = stick_length, $fs =stick_fs);
}

module ornament()
{
    difference() {
        cylinder(r = ornament_size/2, h = stick_diameter);
        translate([0, 0, -stick_diameter/2]) cylinder(r = ornament_size/2 - ornament_thickness, h = stick_diameter*2);
    }
}

module view()
{
     translate([-total_length/2, 0, stick_radius]) {
         cone();
         stick();
    }
    translate([total_length/2 + ornament_size/2 - 0.2, 0, 0]) {
        ornament();
    }
}

//*****************************************************************************

```


[User]
Okay, I'm looking for help creating a parametric, twisted star box in OpenSCAD. I've previously found a design for this box that uses Art of Illusion and a special plugin, but I want to do this directly in OpenSCAD.

I've already created a basic version in OpenSCAD (see below), but I'd like to improve on it, adding a few key features.

My current design uses these parameters:

*   `part`:  A string parameter to specify if we are creating "both" the top and bottom parts, just the "top", or just the "bottom".
*   `$fn`:  A value that controls the smoothness of curves.
*   `iRadius`: The inner radius of the box.
*   `wThickness`:  The wall thickness for the box, lid, and lip.
*   `sbHeight`: The height of the main box body, excluding the lip/top.
*   `sbLip`: The height of the lip on the bottom of the box and the top of the lid.
*   `tFactor`:  A value to control the amount of twist applied to the box and lid.
*   `tGap`: The gap between the lid and the bottom lip for a snug fit.

My current code generates a star-shaped base with an optional lip and a matching star-shaped top/lid.  It uses `linear_extrude` with a twist parameter to create the twisted shape. I've also included a gap to ensure the top fits into the bottom.

I am hoping you can help create a more polished design by taking into account the following considerations:

1.  **Robustness:**  I've used simple differences between cylinders and linear extrudes.  I would like the code to use better methods of generating the star shape and to minimize the use of boolean operations, in particular the difference operation, since it can be slow and is often error-prone. If possible, I'd prefer to avoid boolean operations altogether. Is this possible while still generating a hollow box and lid?

2.  **Precise fit:** The gap ( `tGap`) is currently a simple offset applied to the radius of the lid. I would prefer to have the gap applied directly to the internal profile of the top so that the lid fits the bottom exactly on the non-twisted profile. The twisting can deform the internal fit so it isn't perfectly consistent with a straight sided box. Is it possible to more accurately account for how twisting changes the internal profile?

3.  **Ease of Customization:**  The current method of specifying the star shape as squares is difficult to understand.  I'd like to make it easier to modify the shape to use a different regular polygon for the side of the box and lid. I'd like to add an additional parameter that specifies the number of sides on the box. (e.g. `nSides`) which defaults to 8 (as in the current design), but will allow me to create boxes with a variable number of sides (e.g. a hexagon box, etc.)

4.  **Code Clarity:** I'd like the code to be well organized and commented. Variable names should be descriptive and the code should be easy to read and understand.

5. **Library Use**: I am comfortable with using libraries to achieve my goals, such as BOSL2 for its polygon manipulation tools or other libraries, if necessary. I think that the `linear_extrude` is not working perfectly as it is difficult to see the star profile in the solid. If a library can help me better construct my object I would prefer to use it.

So, I need a fully parametric OpenSCAD design for a twisted box with a matching top/lid, based on a regular polygon, and taking into account the issues noted above, but I'd prefer not to use the `difference` operation if possible. Can you help with this?

[Assistant]
RHM_Star_Box.scad:
```
//------------------------------[ RHM Star Box ]------------------------------
//
//	Author:		    Robert H. Morrison
//	Date:			Sunday, 19 August 2012
//
//	Description:	This is my version of a parametric 8 point star box.
//
//					There are three primary variables: the inner radius (i.e. the
//					size of the hole, the wall Thickness (used for top, bottom
//					and lip) and the star box Height (the height of the box w/o
//					the lip/top.
//
//----------------------------------------------------------------------------

//---[ USER definable Parameters ]--------------------------------------------

part = "both";          // [both:Top and Bottom,top:Top Only,bottom:Bottom Only]

$fn = 100;				//	I found that 100 is a good value for this object

iRadius    =   20;		//	inner Radius
wThickness =    3;		//	wall Thickness
sbHeight   =   93;		//	star box Height

sbLip      =   10;		//	star box Lip height
tFactor    = -100;		//	twist Factor (how twisty)

tGap       =    0.3;	//	the Gap (fudge factor):
						// This is how much of a gap we want to have between
						//	the inside of the top (cap) and the outside of the
						//	bottom lip.  Depends on your printer, but no matter
						//	how well you calibrate your printer it still should
						//	not be zero!

//---[ Automatically calculated Parameters ]----------------------------------

tTwist = (sbHeight * tFactor)/100;	//	true Twist
oRadius = iRadius + wThickness;		//	outer Radius
lSide = 2 * oRadius;				//	length of Side (of a square)

//---[ M O D U L E S ]--------------------------------------------------------

//---[ lip ]------------------------------------------------------------------

module lip() {
	rotate_extrude($fn=200)
		polygon(points=[[oRadius,0],[oRadius,wThickness],[iRadius,wThickness]]);
}

//---[ box ]------------------------------------------------------------------

module box() {
	difference() {
		union() {
			linear_extrude(height = sbHeight, center = false, convexity = 10, twist = tTwist)
				union() {
					rotate([0,0,45])
						square([lSide,lSide], true);
					square([lSide,lSide], true);
				}

			translate([0,0,wThickness])
				cylinder(r=oRadius,h=sbHeight+sbLip);
		}

		translate([0,0,sbHeight+sbLip])
			lip();

		translate([0,0,wThickness])
			cylinder(r=iRadius,h=sbHeight+sbLip+1);
	}
}

//---[ top ]------------------------------------------------------------------

module top() {
	difference() {
		union() {
			linear_extrude(height = sbLip+wThickness+wThickness, center = false, convexity = 10, twist = tTwist*(sbLip+wThickness)/sbHeight)
				union() {
					rotate([0,0,45])
						square([lSide,lSide], true);
					square([lSide,lSide], true);
				}

			translate([0,0,wThickness])
				cylinder(r=oRadius,h=sbLip);
		}

		translate([0,0,wThickness])
			cylinder(r=oRadius+tGap,h=sbLip+wThickness+1);
	}
}

//---[ B E D ]----------------------------------------------------------------

if (part == "bottom")
{
    box();
}
else if (part == "top")
{
    translate([3*lSide/2,0,0])
        top();
}
else if (part == "both")
{
    box();
    translate([3*lSide/2,0,0])
        top();
}

```


[User]
Okay, I need a little help designing a thread spool for my friend's daughter's toy sewing machine. I've got the dimensions all measured out, and I even have some OpenSCAD code I whipped up, but I'd like something a little more flexible and parametric.

Basically, I need a spool that's a cylinder with lips on the top and bottom. Here are the parameters I used in my version, so it would be great if the new version could use these as a starting point:

*   **spool\_radius:** The radius of the main cylindrical part of the spool (half the diameter), currently 8.8 mm
*   **spool\_height:** The height of the main cylindrical part, currently 21.3 mm
*   **lip\_radius:** The radius of the lip at the top and bottom, currently 10.8 mm
*   **lip\_height:** The height of each lip, currently 2.5 mm
*   **spindle\_radius:** The radius of the hole down the center, currently 3.7 mm

I’d like the design to be fully parametric, so if I needed to tweak these measurements later, I could easily do so without digging through a bunch of code. Specifically, I need to be able to set the values of the above variables to create different sized spools.

So, the design should start with a cylinder, then add the "lips" on the top and bottom. Those lips are themselves cylinders, but slightly wider than the main cylinder and in my version, I tapered the connection between the lip and the main cylinder with another cylinder with different radii at the top and bottom. The hole down the center is a simple cylinder subtracted from the whole thing. I've included the code I used as a reference but the important thing is that all those measurements be controllable via variables that I can change.

Also, it would be great if the code was properly commented so it is easy to follow. I don’t have any special requirements beyond basic OpenSCAD functionality. I'm also not using any extra libraries so I don't have to worry about those. Can you help me with that?

[Assistant]
ThreadSpool.scad:
```
/*
Create a thread spool
Created by Mike Creuzer - Mike@Creuzer.com 20120820
Updated 1/14/2013 for Customizer optimization
*/

// Parameters are in mm

// The radius of the spool (half the diameter)
spool_radius = 8.8; // 17.6 / 2 for the toy I used
// The height of the spool
spool_height = 21.3;

// The top and bottom radius
lip_radius = 10.8; // 21.6 / 2 for the toy I used
// The height of the top and bottom
lip_height = 2.5;

// The radius of the whole in the center
spindle_radius = 3.7; // 7.4/2

difference()
{
	union() // Make the spool
	{
		cylinder(r=spool_radius, h=spool_height);
		cylinder(r=lip_radius, h=lip_height);
		translate([0,0,lip_height]) cylinder(r1=lip_radius, r2 = spool_radius, h=lip_height);
		translate([0,0,spool_height-lip_height]) cylinder(r=lip_radius, h=lip_height);
		translate([0,0,spool_height-lip_height-lip_height]) cylinder(r2=lip_radius, r1 = spool_radius, h=lip_height);
	}
	cylinder(r=spindle_radius, h=spool_height); // The hole down the middle
}

```


[User]
Okay, I'd like to design a filament spooling device, something like a "filament daisy" as described in the provided code. The general idea is to have a base that sits on the table, a rotating daisy-shaped piece that holds the filament coil, and a bolt assembly that connects them with bearings. The filament coil sits on the daisy and can freely spin as the printer pulls the filament.

Here's a more detailed breakdown of what I'm after and how I'd like it to be parameterized:

**Overall Design Goals:**

*   **Spool-less Filament Handling:** The device should accommodate a filament coil that's not on a spool. The idea is that the coil will be placed on top of the rotating part (the daisy) and as the filament is pulled by the extruder, the coil will unwind freely.
*   **Stable Base:** The base needs to be stable on a flat surface and have a mount for a bolt assembly.
*   **Rotating Daisy:** This is the core of the design. It should sit on bearings and be able to rotate freely around the bolt axis. It also needs some way to retain a filament coil, likely through an outer perimeter and a central hole for the bolt to pass through.
*   **Bolt Assembly:** I need a way to hold the whole thing together, with a bolt, nut, washers, and bearings to ensure smooth rotation.
*   **Parametric Design:**  I need to be able to adjust all the key dimensions, so that I can customize the design for different filaments and needs.

**Specific Parts and Parameters:**

*   **Bearings:**
    *   `bearing_thickness`:  Thickness of the bearing.
    *   `bearing_od`: Outer diameter of the bearing.
    *   `bearing_id`: Inner diameter of the bearing.

*   **Bolt:**
    *   `bolt_head`: Diameter of the bolt head.
    *   `bolt_extra`: Extra allowance around the bolt features to enable easy printing and assembly.
    *   `bolt_length`: Length of the threaded portion of the bolt.
    *   `bolt_diameter`: Diameter of the bolt shaft.
    *   `bolt_nonlength`: Length of the unthreaded part of the bolt, if any.

*   **Nut:**
    *   `nut_diameter`: Outer diameter of the nut.
    *   `nut_id`: Inner diameter of the nut.
    *   `nut_thickness`: Thickness of the nut.

*   **Washer:**
    *   `washer_diameter`: Outer diameter of the washer.
    *   `washer_id`: Inner diameter of the washer.
    *   `washer_thickness`: Thickness of the washer.

*   **Base:**
    *   `base_od`: Outer diameter of the base.
    *   `base_thickness`: Thickness of the base.
    *   `base_wall`: The thickness of the wall around the central hole for the bolt in the base.
    *   `base_foot`: The size of the 'feet' or supports on the base.

*   **Daisy:**
    *   `daisy_od`: Outer diameter of the daisy.
    *   `daisy_bolt1`: Diameter of the smaller bolt holes on the daisy.
    *   `daisy_bolt2`: Diameter of the larger bolt holes on the daisy.
    *   `daisy_thickness`: Thickness of the daisy.
    *   `daisy_wall`: Thickness of the daisy's outer and inner walls.
    *   `daisy_divider`: The separation between the top and bottom bearing supports in the daisy.
    *   `daisy_offset`: How far the daisy's bolt holes are from the center, as an offset from its radius.

*   **Platform:** (Optional, for later expansion)
    *   `platform_od`: Outer diameter of the platform that would sit on top of the daisy.
    *   `platform_id`: Inner diameter of the platform.
    *   `platform_bolt`:  Bolt hole diameter on the platform.
    *   `platform_offset`: The radial offset of the platform's bolt holes.
    *   `platform_thickness`: Thickness of the platform.

*   **Other:**
    *   `support_layer`: Thickness of support layers used in the design for bridging.
    *   `kerf`: The small clearance between parts for assembly.

**Functionality:**

*   I'd like the OpenSCAD file to generate each component independently (e.g. base(), daisy(), etc.) so I can print them separately and then assemble.
*   The code should calculate the necessary heights for the parts to fit in the assembly with respect to each other, taking into account the bearings, bolt length, etc.
*   I'd also like the option to comment out parts of the assembly, so I can render just the base, or just the daisy for example.
*   It would be great if the design used a `for` loop to generate the four bolt holes around the center of the daisy and base.

**Libraries:**

I don't think I need any specialized libraries, I can accomplish the design using just the built-in OpenSCAD functions.

Can you generate a parametric OpenSCAD file based on these requirements?

[Assistant]
SpoolingDaisy.scad:
```
/*
	Filament Spooling Daisy
	by Cid Vilas
	Cerca 2012
*/

bearing_thickness = 7;
bearing_od = 22;
bearing_id = 8;

bolt_head = 8;
bolt_extra = 3;
bolt_length = 45;
bolt_diameter = 8;
bolt_nonlength = 20;

nut_diameter = 15;
nut_id = 8;
nut_thickness = 3.5;

washer_diameter = 17;
washer_id = 9;
washer_thickness = 1.6;

base_od = 80;
base_thickness = 3;
base_wall = 3;
base_foot = 20;

daisy_od = 70;
daisy_bolt1 = 3;
daisy_bolt2 = 5;
daisy_thickness = 3;
daisy_wall = 3;
daisy_divider = 8;
daisy_offset = 5;

platform_od = 200;
platform_id = 10;
platform_bolt = 5;
platform_offset = daisy_od / 2 - daisy_offset;
platform_thickness = 5;

support_layer = 0.4;

time_separate = 10;

kerf = 1;

module platform()
{
	color([0.6, 0.5, 0.5])
	difference()
	{
		union()
		{
			translate([0, 0, platform_thickness / 2])
			cylinder(r = platform_od / 2, h = platform_thickness, center = true);
		}
		union()
		{
			for(i = [0 : 3])
			{
				rotate([0, 0, i * 90])
				translate([daisy_od / 2 - daisy_offset, 0, platform_thickness / 2])
				cylinder(r = daisy_bolt1 / 2 + kerf, h = platform_thickness + 0.05, center = true);

				rotate([0, 0, i * 90 + 45])
				translate([daisy_od / 2 - daisy_offset, 0, platform_thickness / 2])
				cylinder(r = daisy_bolt2 / 2 + kerf, h = platform_thickness + 0.05, center = true);
			}

			translate([0, 0, platform_thickness / 2])
			cylinder(r = platform_id / 2, h = platform_thickness + 0.05, center = true);
		}
	}
}

module daisy()
{
	color([0, 0.9, 0])
	difference()
	{
		union()
		{
			translate([0, 0, (bearing_thickness * 2 + daisy_divider) / 2])
			cylinder(r = bearing_od / 2 + daisy_wall,
				h = bearing_thickness * 2 + daisy_divider,
				center = true);

			translate([0, 0, daisy_thickness / 2])
			cylinder(r = daisy_od / 2, h = daisy_thickness, center = true);

		}
		union()
		{
			translate([0, 0, bearing_thickness / 2])
			cylinder(r = bearing_od / 2 + kerf,
				h = bearing_thickness + 0.05,
				center = true);

			translate([0, 0, bearing_thickness + daisy_divider + bearing_thickness / 2])
			cylinder(r = bearing_od / 2 + kerf,
				h = bearing_thickness + 0.05,
				center = true);

			translate([0, 0, daisy_divider / 2 + bearing_thickness])
			cylinder(r = bolt_diameter / 2 + kerf,
				h = daisy_divider + 0.05,
				center = true);

			for(i = [0 : 3])
			{
				rotate([0, 0, i * 90])
				translate([daisy_od / 2 - daisy_offset, 0, daisy_thickness / 2])
				cylinder(r = daisy_bolt1 / 2 + kerf, h = daisy_thickness + 0.05, center = true);

				rotate([0, 0, i * 90 + 45])
				translate([daisy_od / 2 - daisy_offset, 0, daisy_thickness / 2])
				cylinder(r = daisy_bolt2 / 2 + kerf, h = daisy_thickness + 0.05, center = true);
			}
		}
	}
	translate([0, 0, bearing_thickness + support_layer / 2])
	cylinder(r = bolt_diameter / 2 + base_wall, h = support_layer, center = true);

}
module base()
{
	color([0, 0.8, 0])
	difference()
	{
		union()
		{
			translate([0, 0, (base_thickness + base_thickness + bolt_nonlength) / 2])
			cylinder(r = (bolt_diameter / 2) + bolt_extra + base_wall,
				h = base_thickness + base_thickness + bolt_nonlength,
				center = true);

			for(i = [0 : 3])
			{
				rotate([0, 0, i * 90])
				translate([0, base_od / 4, base_thickness + base_thickness / 2])
				cube([base_foot / 4,
					base_od / 3,
					base_thickness], center = true);

				rotate([0, 0, i * 90])
				translate([0, base_od / 4, base_thickness / 2])
				cube([base_foot,
					base_od / 2,
					base_thickness], center = true);
			}
		}
		union()
		{
			translate([0, 0, bolt_head / 2])
			cylinder(r = bolt_head / 2 + bolt_extra + kerf, h = bolt_head + 0.05, center = true);

			translate([0, 0, (base_thickness + base_thickness + bolt_nonlength) / 2])
			cylinder(r = bolt_diameter / 2 + kerf,
				h = base_thickness + base_thickness + bolt_nonlength + 0.05,
				center = true);
		}
	}
	translate([0, 0, bolt_head + support_layer / 2])
	cylinder(r = bolt_diameter / 2 + base_wall, h = support_layer, center = true);
}

module nut()
{
	color([0.9, 0.9, 0.9])
	difference()
	{
		union()
		{
			cylinder(r = nut_diameter / 2, h = nut_thickness, center = true, $fn = 6);
		}
		union()
		{
			cylinder(r = nut_id / 2, h = nut_thickness + 0.05, center = true);
		}
	}
}
module washer()
{
	color([0.7, 0.7, 0.7])
	difference()
	{
		cylinder(r = washer_diameter / 2, h = washer_thickness, center = true);
		cylinder(r = washer_id / 2, h = washer_thickness + 0.05, center = true);
	}
}

module bearing()
{
	color([0.8, 0.8, 0.8])
	difference()
	{
		union()
		{
			cylinder(r = bearing_od / 2, h = bearing_thickness, center = true);
		}
		union()
	 	{
			color([0.5, 0.5, 0.5])
			translate([0, 0, bearing_thickness / 2])
			cylinder(r = bearing_od / 2 - 1, h = 0.5, center = true);
			color([0.5, 0.5, 0.5])
			translate([0, 0, -bearing_thickness / 2])
			cylinder(r = bearing_od / 2 - 1, h = 0.5, center = true);

			cylinder(r = bearing_id / 2, h = bearing_thickness + 0.05, center = true);
		}
	}
}

module bolt()
{
	color([0.4, 0.4, 0.4])
	difference()
	{
		union()
		{
			translate([0, 0, -bolt_diameter / 2])
			cylinder(r = bolt_diameter / 2 + bolt_extra, h = bolt_diameter, center = true);

			translate([0, 0, bolt_length / 2])
			cylinder(r = bolt_diameter / 2, h = bolt_length, center = true);
		}
		union()
		{
			translate([0, 0, -bolt_diameter / 2])
			cylinder(r = bolt_diameter / 2, h = bolt_diameter + 0.05, center = true, $fn = 6);
		}
	}
}

cube([110, 110, 0.1], center = true);

translate([0, 0, bolt_diameter - time_separate * $t * 6])
bolt();

translate([0, 0, base_thickness + base_thickness + bolt_nonlength + nut_thickness / 2 + time_separate * $t * 3])
nut();

translate([0, 0,
	base_thickness + base_thickness + bolt_nonlength + nut_thickness + washer_thickness / 2 + time_separate * $t * 4])
washer();

base();

translate([0, 0,
	base_thickness + base_thickness + bolt_nonlength + nut_thickness + washer_thickness + bearing_thickness / 2 + time_separate * $t * 5])
bearing();

translate([0, 0,
	base_thickness + base_thickness + bolt_nonlength + nut_thickness + washer_thickness + bearing_thickness / 2 + 15  + time_separate * $t * 9])
bearing();

translate([0, 0, bolt_head + bolt_length + time_separate * $t * 7])
rotate([180, 0, 0])
daisy();

//translate([0, 0, bolt_length + bolt_head + time_separate * $t * 10])
//platform();

```


[User]
Okay, I need help designing a little part for my toilet seat. It keeps wobbling around, and it's really annoying. I saw this design online, but it's not quite right for my toilet, so I need to make some adjustments, and I’m hoping you can help me create a parametric file for it so I can tweak the dimensions.

Essentially, it's a small bushing that goes around the bolt that holds the toilet seat in place. The idea is that the bushing fills the gap between the bolt and the hole in the toilet, so the seat doesn't move around.

Here are the basic requirements:

1.  **The Main Body:** It's a cylinder that fits into the hole in the toilet. This should have a height that’s variable and a diameter that’s also variable. I'll need to be able to adjust these based on the hole in my toilet.

2.  **The Shoulder/Brim:** There should be a wider, thinner cylinder at the top of the main cylinder. This "brim" will sit on top of the toilet and prevent the bushing from falling into the hole. This also needs variable height and diameter.

3.  **The Bolt Hole:** There's a hole through the center for the bolt to pass through. This hole should have a variable diameter as well, based on the size of my bolt. The bolt hole also needs to be able to be offset from the center of the main cylinder, allowing it to be used if the bolt hole is not in the center of the toilet's hole.

4. **Curve Quality:** The parts are to be rendered at variable curve quality, to allow for faster rendering if the quality is not needed.

I’d like to be able to adjust all of these parameters easily in OpenSCAD using customizer. Here’s a summary of the parameters:

*   `hole_depth`: Depth of the main cylinder part that sits inside the toilet hole
*   `hole_width`: Diameter of the toilet hole
*   `bolt_width`: Diameter of the toilet seat bolt
*   `brim_height`: Height of the wider, top "brim"
*  `brim_width`: The extra width for the brim
*   `hole_offset`: How far off center the bolt hole is, as a percentage of half the difference between the toilet hole diameter and the bolt diameter.
*   `curve_quality_percentage`: A percentage that determines the quality of the rendering.

I think that should cover everything. I'm not too familiar with libraries, but I believe this should be able to be achieved with only basic OpenSCAD functions and no libraries. Can you help me create the OpenSCAD file for this?

[Assistant]
ToiletSeatBoltShim.scad:
```
/*
Toilet seat wobble fixer
This bushing shims the bolt to the toilet so the seat won't wiggle so bad

Mike Creuzer - Mike@Creuzer.com - 2012-08-23
Update 2012-12-23 Added offset to allow for elliptical usage for seats that don't exactly align to the center of the stool's holes.
Update 2013-01-14 Tweaked parameter names for customizer

Measurements are dimensionless but assumed to be in mm for most programs.
*/

//Toilet measurement - maybe make this a bit short if your nut is convex
hole_depth = 10;
//Toilet measurement
hole_width = 16.25;

// Bolt measurement
bolt_width = 9.25;

// Part Measurement - Make this a couple of layers for your printer for good results.
brim_height = 0.6;
// Part Measurement - Shoulder so the shim won't fall out of the hole.
brim_width = 5;
//Percentage to offset the center hole from center.
hole_offset = 75; //  [0:100]
offset = hole_offset * 0.01;
// (factor * by .02) 2 is the default for fast rendering, .01 is as good as it gets.
curve_quality_percentage = 0.5; // [.5:100]
curve_quality = curve_quality_percentage * .02;

difference()
{
	union()
	{
		cylinder(r = hole_width / 2, h=hole_depth, $fs = curve_quality); // The shim
		cylinder(r = (hole_width + brim_width) / 2, h=brim_height); // the shoulder
	}
	translate(v = [offset * ((hole_width-bolt_width) / 2), 0, 0]) cylinder(r = bolt_width / 2, h=hole_depth, $fs = curve_quality); // The bolt hole
}

```


[User]
Okay, I'm looking to generate a customizable grid for small cages or similar applications. I have an existing OpenSCAD file that gets the basic job done, but I'd like to improve it with a few more parameters for better control. Here's what I'm thinking:

My current design uses parameters for:

*   `gridX`: Overall size in the X dimension.
*   `gridY`: Overall size in the Y dimension.
*   `borderX`: The size of the border (empty space) on the X axis.
*   `borderY`: The size of the border (empty space) on the Y axis.
*   `meshSolid`: Width of the solid part of the grid lines.
*   `meshSpace`: Width of the empty space between grid lines.
*  `thickness`: The Z dimension of the grid.

These parameters control a grid where the overall size is defined by `gridX` and `gridY`, the space within that grid is defined by `borderX` and `borderY`, the grid lines are defined by `meshSolid` and `meshSpace`, and the thickness is defined by `thickness`.

I would like to add the following to the parameters and functionality:

1.  **Rounded Corners:**  I'd like to have an optional parameter called `cornerRadius` that, if set to a value greater than zero, will round the corners of the entire grid (the outer rectangle).
2.  **Grid Line End Type:** It would be great to have an additional parameter to control the ends of the grid lines. This parameter `lineEndType` could accept values such as:
	*   `square` (or `none`, just the normal flat end)
	*   `round` (a half cylinder capping the lines)
	*   `chamfer` (an angled end).
	These options should apply both in the X and Y direction.
3.  **Line End Length:** Depending on the `lineEndType`, the grid lines may need to extend slightly, for instance when capping a line with a round end or with a chamfered end.  This extension should be controlled by a parameter named `lineEndExtension`, applied as a length.
4.  **Optional Base:** Sometimes, I want the grid to have a solid base to increase rigidity, I would like a parameter called `baseThickness` that if set greater than 0 will add a solid plate to the bottom of the grid.

Finally, I'd like to request that the generated OpenSCAD file include:
* A reasonable module for the grid so it can be easily instantiated with the parameters.
* Commenting on the code explaining what is going on, where it makes sense.

I would prefer to use standard OpenSCAD code if possible, but I am familiar with using the MCAD library if that proves useful. I don't have any strong preference on which features of the library would be used, if any, as long as the resulting code is relatively easy to understand.

In summary, please provide a parameterized OpenSCAD file that creates a customizable grid, incorporating rounded corners, different end types for the grid lines, extending line ends depending on the type, and an optional base. Thank you.

[Assistant]
grid.scad:
```
//------------parameters---------------------------
// overall size of X dimension
gridX=100;
// overall size of Y dimension
gridY=100;
// X border size
borderX=10;
// Y border size
borderY=10;
// width of solid part of grid
meshSolid=0.5;
// width of blank part of grid
meshSpace=2;
// thickness in Z direction
thickness=1.5;

//-------------------------------------------------
meshX=gridX-(borderX*2);
meshY=gridY-(borderY*2);
nX=meshX/(meshSolid+meshSpace);
nY=meshY/(meshSolid+meshSpace);

difference() {
cube (size=[gridX,gridY,thickness],center=true);
cube (size=[meshX,meshY,thickness],center=true);
}

for (i=[0:nX]) {
	 	 translate([-(meshX/2)+i*(meshSolid+meshSpace),-meshY/2,-thickness/2]) cube(size=[meshSolid,meshY,thickness],center=false);
}

for (i=[0:nY]) {
	 	translate([-meshX/2,-(meshY/2)+i*(meshSolid+meshSpace),-thickness/2]) cube(size=[meshX,meshSolid,thickness],center=false);

}

```


[User]
Okay, I need a parametric OpenSCAD design for a hook that I can screw into a wall, and I have a pretty specific starting point in mind, based on another file I've been working with.

Basically, I want to take the nub-like object described in the "Nub_Hook.scad" file I provided, which has a cylindrical body and a spherical top, and add a screw hole and some kind of flange or base that will allow it to be screwed into a wall.

Here are the parameters I'd like to be able to control:

*   **`HOEHE` (Height):** This controls the height of the central cylindrical section of the nub, and the position of the spherical top. I'd like to retain the same behaviour where the sphere is centered on top.
*   **`FUESSE` (Number of feet/supports):** I'd like to keep the option of adding those decorative feet around the base that are in my original file.
*   **Central Nub Dimensions:** The nub itself should retain the same basic dimensions from the "Nub_Hook.scad" file, particularly the cylinder radius (0.8) and sphere radius (1.5), as well as the 6x6x1 base.
*   **Mounting Base:** I need a flat base to attach the nub to the wall. This should extend beyond the 6x6x1 base of the nub and should have countersunk screw holes.
*   **Countersunk Screw Holes:** I need to be able to specify how many screw holes, their diameter, their position and the countersunk angle. I'd like to be able to specify if it should be centered and/or how far from center. I'd like it if there was a way to easily change them between even or odd amounts of screws (if they are centered), or to manually place them on a circle. I'd like to be able to define screw hole diameter and countersink diameter separately.
*   **Base Thickness:** The thickness of the mounting base should also be a parameter.
*   **Nub Base Connection:** I want the nub to be firmly attached to this mounting base.  The cylinder and cube from the original file should be connected to it as a single unit, not as just objects on the same plane.

I'd like to be able to use the `MCAD` library for the screw hole functionality, specifically `screw_hole()`. I think it might be helpful to have a parameter that allows me to specify the screw type, and that would then update the countersink and screw hole diameter. If I specify no screw type, I'd like to be able to manually specify diameters and a countersink angle.

I am attaching my original "Nub_Hook.scad" for reference. The critical part is the initial base and the nub:

```
$fn    = 40*1; // For Customizer

// Nr of foots
FUESSE = 3; // [0:8]

// Height
HOEHE  = 6; // [3:15]

difference() {
   cube([6,6,1], true);
	for(j = [1:4]) {
		rotate(j*360/4, [0, 0, 1]) {
    			translate([2.3, 2.3, -1]) cylinder(h=2, r=0.2);
		}
	}
}

translate([0,0,HOEHE/2]) {
    cylinder(h=HOEHE, r=0.8, center = true);
    translate([0,0,HOEHE/2]) {
        sphere(1.5);
    }
}

for (i = [1:FUESSE]) {
	rotate(270, [0,1,0]) {
	    translate([0.5,0,0]) {
			rotate((i*360 / FUESSE) + 21, [1,0,0]) {
				linear_extrude(height = 1, center = true) polygon(points=[[0,0],[3,0],[0,1.9]], paths=[[1,2,0]]);
			}
		}
	}
}
```

Let me know if you have any questions, thanks!

[Assistant]
Nub_Hook.scad:
```
$fn    = 40*1; // For Customizer

// Nr of foots
FUESSE = 3; // [0:8]

// Height
HOEHE  = 6; // [3:15]

difference() {
   cube([6,6,1], true);
	for(j = [1:4]) {
		rotate(j*360/4, [0, 0, 1]) {
    			translate([2.3, 2.3, -1]) cylinder(h=2, r=0.2);
		}
	}
}

translate([0,0,HOEHE/2]) {
    cylinder(h=HOEHE, r=0.8, center = true);
    translate([0,0,HOEHE/2]) {
        sphere(1.5);
    }
}

for (i = [1:FUESSE]) {
	rotate(270, [0,1,0]) {
	    translate([0.5,0,0]) {
			rotate((i*360 / FUESSE) + 21, [1,0,0]) {
				linear_extrude(height = 1, center = true) polygon(points=[[0,0],[3,0],[0,1.9]], paths=[[1,2,0]]);
			}
		}
	}
}

```


[User]
Okay, I'm looking for an OpenSCAD design for a rod clamp, but I want it to be more flexible and configurable than the one I'm currently using. The basic idea is still a clamp that connects two rods at an adjustable angle, but I need more parameters to control the design.

Here's what I'm envisioning:

*   **Rod Diameter:** This needs to be a variable, not just fixed at 8mm. I want to be able to specify the rod diameter as a parameter, `rod_dia`.
*   **Clamp Wall Thickness:** The thickness of the clamp material, `wall`, needs to be adjustable.
*   **Screw Diameter:** The diameter of the screw used to tighten the clamp, `screw_dia`, also needs to be a parameter.
*   **Gap Between Clamps:** The space or `gap` between the two halves of the clamp (where the rod is inserted) should be configurable.
*   **Screw Separation:** The distance between the screw hole and the rod, `screw_separation`, should also be a parameter.
*  **Clamp Angle:**  The angle between the two rods needs to be adjustable.  I want to set this as an angle parameter, `clamp_angle`. I'd like it to be adjustable within a practical range (e.g. maybe 30 to 150 degrees), but perhaps the program can throw an error if I input an out-of-range value.
*   **Beveled Edges:**  I'd like an optional bevel on the edges of the clamp. This could be toggled with a `bevel` parameter (1 for on, 0 for off), and I'd also like to be able to control how big the bevel is, maybe using a `bevel_size` parameter.
*   **Smooth Channel:**  An option to smooth the edges of the channel, similar to the existing code, should be controlled by a `smooth` parameter (1 for on, 0 for off).
*  **Number of Clamp Sections:** Right now the clamp is a two-part clamp with a 45 degree angle between those parts. I'd like to have a variable `clamp_sections` which would enable the design to have more than two clamping sections, for example 3 sections with a 30 degree angle between sections. The default should be two sections. When using multiple sections the angle between each section should be the value of `clamp_angle` divided by `clamp_sections-1`.
* **Screw Countersink:** I would like to have a countersink feature for the screw holes. The depth and countersink diameters should be configurable with `countersink_depth` and `countersink_dia` parameters.
*   **Render Movable Parts:** A debug option, `render_movable_parts`, would be useful to optionally show the rod during debugging but otherwise to omit it.

I'd like to avoid using any external libraries if possible, but if it's truly needed, I'd prefer something like BOSL2 since I've had some experience with that library, but please tell me which parts of the library are used in your response.

The current code I'm using can be found below, if that's helpful.

```
// Rod diameter
rod_dia=8;
// Wall thickness
wall=3;
// Screw diameter
screw_dia=3;
// Gap between clamps.
gap=2;
// Space between screw and rod.
screw_separation=1;
// Bevel
bevel=1;  //  [1, 0]
// Smooth channel
smooth=1;  //  [1, 0]

/* [Hidden] */
render_movable_parts = false;

module rod() {
  color([0.7, 0.7, 0.7]) {
    rotate([0,0,180/8])
      cylinder(r=rod_dia/2/cos(180/8), h=80, $fn=smooth ? 23 : 8, center=true);
  }
}

module clamp() {
  dia = rod_dia + screw_dia/2 + screw_separation+ wall;
  difference() {
    rotate([0,90,0])  {
      rotate([0,0,45/2]) {
	translate([0,0,gap / 2]) {
	  cylinder(r=dia/cos(180/8),
		   h=rod_dia+wall-gap / 2, $fn=8);
	}
      }
    }
    if (bevel) {
      for (rot=[0:45:360]) {
        rotate([rot,0,0]) {
  	  translate([rod_dia+wall,dia,0]) {
	    rotate([0,0,45]) {
	      cube([wall*2 * cos(180/4) - 0.2, 100, 100], center=true);
            }
	  }
        }
      }
    }
    translate([rod_dia/2,
	       (rod_dia+screw_dia+screw_separation)/2,0]) {
      rod();
      translate([-rod_dia/2, 0,0]) {
      cube([rod_dia, rod_dia, 100], center=true);
      }
    }
    rotate([0,90,0])  {
      cylinder(r=screw_dia/2, $fn=10, h = 100, center=true);
    }
  }
  if (render_movable_parts) {
    translate([rod_dia/2, (rod_dia+screw_dia+screw_separation)/2,0]) rod();
  }
}

rotate([0,90,0]) {
  translate([gap / 2,0,0]) {
    if (render_movable_parts) {
      clamp();
    }

    rotate([45,180,0]) clamp();
  }
}
```

[Assistant]
angled-rod-clamp.scad:
```
// Rod diameter
rod_dia=8;
// Wall thickness
wall=3;
// Screw diameter
screw_dia=3;
// Gap between clamps.
gap=2;
// Space between screw and rod.
screw_separation=1;
// Bevel
bevel=1;  //  [1, 0]
// Smooth channel
smooth=1;  //  [1, 0]

/* [Hidden] */
render_movable_parts = false;

module rod() {
  color([0.7, 0.7, 0.7]) {
    rotate([0,0,180/8])
      cylinder(r=rod_dia/2/cos(180/8), h=80, $fn=smooth ? 23 : 8, center=true);
  }
}

module clamp() {
  dia = rod_dia + screw_dia/2 + screw_separation+ wall;
  difference() {
    rotate([0,90,0])  {
      rotate([0,0,45/2]) {
	translate([0,0,gap / 2]) {
	  cylinder(r=dia/cos(180/8),
		   h=rod_dia+wall-gap / 2, $fn=8);
	}
      }
    }
    if (bevel) {
      for (rot=[0:45:360]) {
        rotate([rot,0,0]) {
  	  translate([rod_dia+wall,dia,0]) {
	    rotate([0,0,45]) {
	      cube([wall*2 * cos(180/4) - 0.2, 100, 100], center=true);
            }
	  }
        }
      }
    }
    translate([rod_dia/2,
	       (rod_dia+screw_dia+screw_separation)/2,0]) {
      rod();
      translate([-rod_dia/2, 0,0]) {
      cube([rod_dia, rod_dia, 100], center=true);
      }
    }
    rotate([0,90,0])  {
      cylinder(r=screw_dia/2, $fn=10, h = 100, center=true);
    }
  }
  if (render_movable_parts) {
    translate([rod_dia/2, (rod_dia+screw_dia+screw_separation)/2,0]) rod();
  }
}

rotate([0,90,0]) {
  translate([gap / 2,0,0]) {
    if (render_movable_parts) {
      clamp();
    }

    rotate([45,180,0]) clamp();
  }
}

```


[User]
Okay, I'm looking to design a mount that attaches a specific type of laser lens directly to a Reci CO2 laser tube. I've got some existing code that does this, but it's a bit monolithic and I'd really like to make it more parametric and easier to adapt for different lens and tube sizes.

Here's the basic idea: I need a cylindrical piece that slides over the end of a Reci laser tube. This cylinder has to be fairly thick to be stable, so I need to be able to adjust its wall thickness and height. On the other end of this cylinder, I need a threaded mount for the laser lens.

Here are the key parameters I'm looking to control:

*   **`lensMountDiameter`**: The diameter of the threads on the laser lens mount. This needs to be adjustable. For my current setup, this is 14mm, but I might have other sizes in the future. The current code defaults to a fine (1mm pitch) thread if the diameter is 14mm, and course threads for other sizes, this is important.
*   **`exteriorTubeDiameter`**: The outer diameter of the Reci laser tube. Currently set for the Reci W6 tube at 27.64mm. I need to be able to adjust this for other tubes.
*   **`tubeHeight`**: The length of the cylindrical tube section that slides over the laser tube. This is currently 15mm, but I'd like to be able to adjust it.
*   **`tubeWallThickNess`**: The thickness of the walls of the cylindrical tube section. This is currently 3mm, but I need it to be a parameter.
*   **`collarHeight`**: A small collar area near the lens mount, I need it to be a parameter. This is currently 3mm.

The code I have also uses a thread library, which is really nice. I'd like the AI to reuse it. Here are the key details of the library usage:

*   The library uses functions called `get_thr_qual` and `get_sh_qual` to determine the number of segments used in the thread. These functions use lookup tables. I will not attach the libraries but I expect you to understand the functionality I described.
*   The library uses a function `get_coarse_pitch` to lookup the thread pitch based on diameter, using a lookup table. I need to make sure that if the `lensMountDiameter` is 14mm, the pitch is forced to 1mm for a fine thread, if I set a different value it should default to the correct course pitch.
*   The library also has modules `hex_nut`, `hex_bolt`, `thread_out`, `thread_in`, `th_out_pt`, and `th_in_pt`.
*   The library uses lookup tables `hex_nut_dia`, `hex_nut_hi`, `hex_bolt_dia`, `hex_bolt_hi`.

I need a version that utilizes the existing thread library. The existing code also rotates the part 180 degrees on the Y-axis, please retain this functionality.

Can you write a parametric OpenSCAD file based on the above using this thread library? I expect the file to be self contained, so there's no need to import any .scad files, the functions/modules should be inside this file. The library code is fine but will need to be made a bit more robust, as it only covers a portion of thread sizes.

[Assistant]
reci-tube-lens-interface.scad:
```
//
// Reci CO2 Laser Head Direct Mount
// Jeshua Lacock
// 9/13/2012
//
// Current settings work for:
// http://www.lightobject.com/1820mm-Laser-head-w-air-assisted-Ideal-for-K40-machine-P701.aspx
// with:
// http://www.recilaser.com/2010/en_product/W6_en.html
//
// Printed at 101%, use slic3r and fits the laser tube and laser head perfectly.
//
// Based on the awesome:
//
// ISO Metric Thread Implementation
// Trevor Moseley
// 23/08/2012
//
// For thread dimensions see
//   http://en.wikipedia.org/wiki/File:ISO_and_UTS_Thread_Dimensions.svg

fn_value = 50;

//my lens is 14mm fine thread. I only changed the thread to fine (1mm) for the 14mm value. If you use another size than 14mm, and you need fine thread, change the value in "get_coarse_pitch" below (otherwise course thread will be used). The first number is the diameter (eg 14mm) and the next number is the thread pitch.

lensMountDiameter = 14; //diameter of thread on the lens mount
exteriorTubeDiameter = 27.64; //diameter of the tube to mount to, this works perfectly for the Reci W6. I think the other Reci are the sams size
tubeHeight = 15;
tubeWallThickNess = 3;
collarHeight = 3;

rotate(a=[0,180,0]) {

union() {

hex_nut(lensMountDiameter);

			difference()
			{
				translate( [0,0,(collarHeight/2)+collarHeight] )

					cylinder( h = collarHeight, r = (exteriorTubeDiameter * 0.5) +tubeWallThickNess, center = true );
				translate( [0,0,collarHeight+0.1] )
cylinder( h = collarHeight*2, r = (lensMountDiameter * 0.5), center = true );
			} //end diference() of thread tube.

			difference()
			{
				translate( [0,0,(tubeHeight/2)+collarHeight] )

					cylinder( h = tubeHeight, r = (exteriorTubeDiameter * 0.5) + tubeWallThickNess, center = true );
				translate( [0,0,tubeHeight+collarHeight] )
				cylinder( h = 100, r = (exteriorTubeDiameter * 0.5), center = true );
			} //end diference() of thread tube.

}

}

defQ = 32;

// function for thread quality
function get_thr_qual(dia) = lookup(dia, [
[5,10],[6,12],[7,14],[8,16],[10,20],[12,12],[14,28],[16,32],[18,36],[20,40],[22,44],[24,48],[27,54],[30,60],[33,66],[36,72],[39,78],[42,84],[45,90],[48,96],[52,104],[56,112],[60,120],[64,128],[78,156]]);

// function for shaft quality
function get_sh_qual(dia) = lookup(dia, [
[5,10],[6,12],[7,14],[8,16],[10,20],[12,24],[14,28],[16,32],[18,36],[20,40],[22,44],[24,48],[27,54],[30,60],[33,66],[36,72],[39,78],[42,84],[45,90],[48,96],[52,104],[56,112],[60,120],[64,128],[78,156]]);

module hex_nut(dia)
{
	$fn = get_sh_qual(dia);
	thr = get_thr_qual(dia);
	hi = hex_nut_hi(dia);
	difference()
	{
		cylinder(r = hex_nut_dia(dia)/2,h = hi, $fn=6);
		translate([0,0,-0.1])	cylinder(r = dia/2, h =hi + 0.2);
	}
	translate([0,0,0.1])	thread_in(dia,hi-0.2,thr);
}

module hex_bolt(dia,hi)
{
	$fn = get_sh_qual(dia);
	thr = get_thr_qual(dia);
	hhi = hex_bolt_hi(dia);
	cylinder(r = hex_bolt_dia(dia)/2,h = hhi, $fn=6);
	translate([0,0,hhi-0.1])	thread_out(dia,hi+0.1,thr);
}

// function for thread pitch
function get_coarse_pitch(dia) = lookup(dia, [
[1,0.25],[1.2,0.25],[1.4,0.3],[1.6,0.35],[1.8,0.35],[2,0.4],[2.5,0.45],[3,0.5],[3.5,0.6],[4,0.7],[5,0.8],[6,1],[7,1],[8,1.25],[10,1.5],[12,1.75],[14,1],[16,2],[18,2.5],[20,2.5],[22,2.5],[24,3],[27,3],[30,3.5],[33,3.5],[36,4],[39,4],[42,4.5],[45,4.5],[48,5],[52,5],[56,5.5],[60,5.5],[64,6],[78,5]]);

// function for hex nut diameter from thread size
function hex_nut_dia(dia) = lookup(dia, [
[3,6.4],[4,8.1],[5,9.2],[6,11.5],[8,16.0],[10,19.6],[12,22.1],[16,27.7],[20,34.6],[24,41.6],[30,53.1],[36,63.5]]);
// function for hex nut height from thread size
function hex_nut_hi(dia) = lookup(dia, [
[3,2.4],[4,3.2],[5,4],[6,3],[8,5],[10,5],[12,10],[14,5],[16,13],[20,16],[24,19],[30,24],[36,29]]);

// function for hex bolt head diameter from thread size
function hex_bolt_dia(dia) = lookup(dia, [
[3,6.4],[4,8.1],[5,9.2],[6,11.5],[8,14.0],[10,16],[12,22.1],[16,27.7],[20,34.6],[24,41.6],[30,53.1],[36,63.5]]);
// function for hex bolt head height from thread size
function hex_bolt_hi(dia) = lookup(dia, [
[3,2.4],[4,3.2],[5,4],[6,3.5],[8,4.5],[10,5],[12,10],[16,13],[20,16],[24,19],[30,24],[36,29]]);

module thread_out(dia,hi,thr=defQ)
{
	p = get_coarse_pitch(dia);
	h = (cos(30)*p)/8;
	Rmin = (dia/2) - (5*h);	// as wiki Dmin
	s = 360/thr;
	t = (hi-p)/p;			// number of turns
	n = t*thr;				// number of segments
	//echo(str("dia=",dia," hi=",hi," p=",p," h=",h," Rmin=",Rmin," s=",s));
	cylinder(r = Rmin, h = hi);
	for(sg=[0:n])
		th_out_pt(Rmin-0.1,p,s,sg,thr,h,(hi-p)/n);
}

module th_out_pt(rt,p,s,sg,thr,h,sh)
// rt = radius of thread (nearest centre)
// p = pitch
// s = segment length (degrees)
// sg = segment number
// thr = segments in circumference
// h = ISO h of thread / 8
// sh = segment height (z)
{
	as = (sg % thr) * s;			// angle to start of seg
	ae = as + s  - (s/100);		// angle to end of seg (with overlap)
	z = sh*sg;

	cas=cos(as);
	sas=sin(as);
	cae=cos(ae);
	sae=sin(ae);
	rtp=rt+(5*h);

	casrt=cas*rt;
	sasrt=sas*rt;
	caert=cae*rt;
	saert=sae*rt;

	//   1,4
	//   |\
	//   |  \  2,5
 	//   |  /
	//   |/
	//   0,3
	//  view from front (x & z) extruded in y by sg
	//
	//echo(str("as=",as,", ae=",ae," z=",z));
	polyhedron(
		points = [
			[casrt,sasrt,z],					// 0
			[casrt,sasrt,z+(3/4*p)],			// 1
			[cas*rtp,sas*rtp,z+(3/8*p)],		// 2
			[caert,saert,z+sh],				// 3
			[caert,saert,z+(3/4*p)+sh],		// 4
			[cae*rtp,sae*rtp,z+sh+(3/8*p)]],	// 5
		triangles = [
			[0,1,2],			// near face
			[3,5,4],			// far face
			[0,3,4],[0,4,1],	// left face
			[0,5,3],[0,2,5],	// bottom face
			[1,4,5],[1,5,2]]);	// top face
}

module thread_in(dia,hi,thr=defQ)
{
	p = get_coarse_pitch(dia);
	h = (cos(30)*p)/8;
	Rmin = (dia/2) - (5*h);	// as wiki Dmin
	s = 360/thr;
	t = (hi-p)/p;			// number of turns
	n = t*thr;				// number of segments
	//echo(str("dia=",dia," hi=",hi," p=",p," h=",h," Rmin=",Rmin," s=",s));
	difference()
	{
		cylinder(r = (dia/2)+0.5,h = hi);
		translate([0,0,-1]) cylinder(r = (dia/2)+0.1, h = hi+2);
	}
	for(sg=[0:n])
		th_in_pt(Rmin+0.2,p,s,sg,thr,h,(hi-p)/n);
}

module th_in_pt(rt,p,s,sg,thr,h,sh)
// rt = radius of thread (nearest centre)
// p = pitch
// s = segment length (degrees)
// sg = segment number
// thr = segments in circumference
// h = ISO h of thread / 8
// sh = segment height (z)
{
//	as = 360 - (((sg % thr) * s) - 180);	// angle to start of seg
//	ae = as - s + (s/100);		// angle to end of seg (with overlap)
	as = ((sg % thr) * s - 180);	// angle to start of seg
	ae = as + s -(s/100);		// angle to end of seg (with overlap)
	z = sh*sg;

	cas=cos(as);
	sas=sin(as);
	cae=cos(ae);
	sae=sin(ae);
	rtp=rt+(5*h);

	casrt=cas*rt;
	casrtp=cas*rtp;
	sasrt=sas*rt;
	sasrtp=sas*rtp;
	caert=cae*rt;
	caertp=cae*rtp;
	saert=sae*rt;
	saertp=sae*rtp;

	//         2,5
	//          /|
	//  1,4 /  |
 	//        \  |
	//          \|
	//         0,3
	//  view from front (x & z) extruded in y by sg
	//
	polyhedron(
		points = [
			[casrtp,sasrtp,z],				//0
			[casrt,sasrt,z+(3/8*p)],			//1
			[casrtp,sasrtp,z+(3/4*p)],		//2
			[caertp,saertp,z+sh],			//3
			[caert,saert,z+(3/8*p)+sh],		//4
			[caertp,saertp,z+(3/4*p)+sh]],	//5
		triangles = [
			[0,1,2],			// near face
			[3,5,4],			// far face
			[0,3,4],[0,4,1],	// left face
			[0,5,3],[0,2,5],	// bottom face
			[1,4,5],[1,5,2]]);	// top face
}

```