Geekhaus Link: https://geekhaus.com/isci104_spring2019/2019/04/11/hannah-and-graces-openscad-project/

Customizable Lego Ring

To customize: change the parameters:

outer_size with the range of (9-12)
outer_thickness with the range of (1-5)
block_width with the range of (1-4)
block_length with the range of (1-4)

Code:
//Ring module
$fn=50;
// customisable ring size
outer_size = 10;
outer_thickness= 4;
size = 8;
thickness = 5;
//customisable lego dimensions
//Code Credit// Christopher Finke @cfinke on GitHub
block_width = 2;
block_length = 2;

difference (){
cylinder(r=outer_size, h=outer_thickness, center=true);
cylinder(r=size, h=thickness, center=true);
}
translate([10,0,0])
rotate([0,-90,0])
cylinder(h=2, r1=4, r2=1, center=true);

// Height of the block. A ratio of "1" is a standard LEGO brick height; a ratio of "1/3" is a standard LEGO plate height; "1/2" is a standard DUPLO plate.
block_height_ratio = .1; // [.33333333333:1/3, .5:1/2, 1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8, 9:9, 10:10]

// What type of block should this be? For type-specific options, see the "Wings," "Slopes," "Curves", and "Baseplates" tabs.
block_type = "brick"; // [brick:Brick, tile:Tile, wing:Wing, slope:Slope, curve:Curve, baseplate:Baseplate]

// What brand of block should this be? LEGO for regular LEGO bricks, Duplo for the toddler-focused larger bricks.
block_brand = "lego"; // [lego:LEGO, duplo:DUPLO]

// What stud type do you want? Hollow studs allow rods to be pushed into the stud.
stud_type = "solid"; // [solid:Solid, hollow:Hollow]

// Should the block include round horizontal holes like the Technics LEGO bricks have?
technic_holes = "no"; // [no:No, yes:Yes]

// Should the block include vertical cross-shaped axle holes?
vertical_axle_holes = "no"; // [no:No, yes:Yes]

/ [Wings] /

// What type of wing? Full is suitable for the front of a plane, left/right are for the left/right of a plane.
wing_type = "full"; // [full:Full, left:Left, right:Right]

// The number of studs across the end of the wing. If block_width is odd, this needs to be odd, and the same for even.
wing_end_width = 2;

// The length of the rectangular portion of the wing, in studs.
wing_base_length = 3;

// Should the wing edges be notched to accept studs below?
wing_stud_notches = "yes"; // [yes:Yes, no:No]

/ [Slopes] /

// How many rows of studs should be left before the slope?
slope_stud_rows = 1;

// How much vertical height should be left at the end of the slope? e.g, a value of zero means the slope reaches the bottom of the block. A value of 1 means that for a block with height 2, the slope reaches halfway down the block.
slope_end_height = 0;

/ [Curves] /

// How many rows of studs should be left before the curve?
curve_stud_rows = 5;

// Should the curve be convex or concave?
curve_type = "concave"; // [concave:Concave, convex:Convex]

// How much vertical height should be left at the end of the curve? e.g, a value of zero means the curve reaches the bottom of the block. A value of 1 means that for a block with height 2, the curve reaches halfway down the block.
curve_end_height = 0;

/ [Baseplates] /

// If you want a roadway, how wide should it be (in studs)? A roadway is a smooth (non-studded) section of a baseplate.
roadway_width = 0;

// How long should the roadway be?
roadway_length = 0;

// Where should the roadway start (x-value)? A value of zero puts the roadway at the far left side of the plate.
roadway_x = 0;

// Where should the roadway start (y-value)? A value of zero puts the roadway at the front of the plate.
roadway_y = 0;

/ [SNOT] /

// SNOT means Studs Not On Top -- bricks with alternative stud configurations.
// Put studs on the top and buttom?
dual_sided = "no"; // [no:No, yes:Yes]

// Instead of both sides having studs, both sides can have no studs.
dual_bottom = "no"; // [no:No, yes:Yes]

/ [Printer-Specific] /

// Should extra reinforcement be included to make printing on an FDM printer easier? Ignored for tiles, since they're printed upside-down and don't need the reinforcement. Recommended for block heights less than 1 or for Duplo bricks.
use_reinforcement = "no"; // [no:No, yes:Yes]

// If your printer prints the blocks correctly except for the stud diameter, use this variable to resize just the studs for your printer. A value of 1.05 will print the studs 105% wider than standard.
stud_rescale = 1;
//stud_rescale = 1.0475 1; // Orion Delta, T-Glase
//stud_rescale = 1.022 1; // Orion Delta, ABS

// Print tiles upside down.
translate([9,0,0])
rotate([0,90,0])
translate([0, 0, (block_type == "tile" ? block_height_ratio * block_height : 0)]) rotate([0, (block_type == "tile" ? 180 : 0), 0]) {
block(
width=block_width,
length=block_length,
height=block_height_ratio,
type=block_type,
brand=block_brand,
stud_type=stud_type,
horizontal_holes=(technic_holes=="yes"),
vertical_axle_holes=(vertical_axle_holes=="yes"),
reinforcement=(use_reinforcement=="yes"),
wing_type=wing_type,
wing_end_width=wing_end_width,
wing_base_length=wing_base_length,
stud_notches=(wing_stud_notches=="yes"),
slope_stud_rows=slope_stud_rows,
slope_end_height=slope_end_height,
curve_stud_rows=curve_stud_rows,
curve_type=curve_type,
curve_end_height=curve_end_height,
roadway_width=roadway_width,
roadway_length=roadway_length,
roadway_x=roadway_x,
roadway_y=roadway_y,
stud_rescale=stud_rescale,
dual_sided=(dual_sided=="yes"),
dual_bottom=(dual_bottom=="yes")
);
}

module block(
width=1,
length=2,
height=1,
type="brick",
brand="lego",
stud_type="solid",
horizontal_holes=false,
vertical_axle_holes=false,
reinforcement=false,
wing_type="full",
wing_end_width=2,
wing_base_length=2,
stud_notches=false,
slope_stud_rows=1,
slope_end_height=0,
curve_stud_rows=1,
curve_type="concave",
curve_end_height=0,
roadway_width=0,
roadway_length=0,
roadway_x=0,
roadway_y=0,
stud_rescale=1,
dual_sided=false,
dual_bottom=false
) {
post_wall_thickness = (brand == "lego" ? 0.85 : 1);
wall_thickness=(brand == "lego" ? 1.45 : 1.5);
stud_diameter=(brand == "lego" ? 4.85 : 9.35);
hollow_stud_inner_diameter = (brand == "lego" ? 3.1 : 6.7);
stud_height=(brand == "lego" ? 1.8 : 4.4);
stud_spacing=(brand == "lego" ? 8 : 8 2);
block_height=(brand == "lego" ? (type == "baseplate" ? 1.3 : 9.6) : 9.6 2);
pin_diameter=(brand == "lego" ? 3 : 3 * 2);
post_diameter=(brand == "lego" ? 6.5 : 13.2);
cylinder_precision=(brand == "lego" ? 0.1 : 0.05);
reinforcing_width = (brand == "lego" ? 0.7 : 1);

spline_length = (brand == "lego" ? 0.25 : 1.7);spline_thickness = (brand == "lego" ? 0.7 : 1.3);horizontal_hole_diameter = (brand == "lego" ? 4.8 : 4.8 * 2);horizontal_hole_z_offset = (brand == "lego" ? 5.8 : 5.8 * 2);horizontal_hole_bevel_diameter = (brand == "lego" ? 6.2 : 6.2 * 2);horizontal_hole_bevel_depth = (brand == "lego" ? 0.9 : 0.9 * 1.5 / 1.2 );roof_thickness = (type == "baseplate" || dual_sided ? block_height * height : 1 * 1);// Brand-independent measurements.axle_spline_width = 2.0;axle_diameter = 5 * 1;wall_play = 0.1 * 1;horizontal_hole_wall_thickness = 1 * 1;// Ensure that width is always less than or equal to length.real_width = (type == "wing" ? width : min(width, length) );real_length = (type == "wing" ? length : max(width, length) );real_height = max((type == "baseplate" ? 1 : 1/3), height);// Ensure that the wing end width is even if the width is even, odd if odd, and a reasonable value.real_wing_end_width = (wing_type == "full"    ?    min(real_width - 2, ((real_width % 2 == 0) ?         (max(2, (            wing_end_width % 2 == 0 ?            (wing_end_width)            :            (wing_end_width-1)        )))        :        (max(1, (            wing_end_width % 2 == 0 ?            (wing_end_width-1)            :            (wing_end_width)        )))    ))    :    (min(real_width-1, max(1, wing_end_width))) // Half-wing);// Ensure that the base length is a reasonable value.real_wing_base_length = min(real_length-1, max(1, wing_base_length)) + 1; // +1 because the angle starts before the last stud.// Validate all the rest of the arguments.real_slope_end_height = max(0, min(real_height - 1/3, slope_end_height));real_slope_stud_rows = min(real_length - 1, slope_stud_rows);real_curve_stud_rows = max(0, curve_stud_rows);real_curve_type = (curve_type == "convex" ? "convex" : "concave");real_curve_end_height = max(0, min(real_height - 1/3, curve_end_height));real_horizontal_holes = horizontal_holes && ((type == "baseplate" && real_height >= 8) || real_height >= 1) && !dual_sided;real_vertical_axle_holes = vertical_axle_holes && real_width > 1;real_reinforcement = reinforcement && type != "baseplate" && type != "tile" && !dual_sided;real_roadway_width = max(0, min(roadway_width, real_width));real_roadway_length = max(0, min(roadway_length, real_length));real_roadway_x = max(0, min(real_length - real_roadway_length, roadway_x));real_roadway_y = max(0, min(real_width - real_roadway_width, roadway_y));real_stud_notches = stud_notches && !dual_sided;real_dual_sided = dual_sided && type != "curve" && type != "slope" && type != "tile";real_dual_bottom = dual_bottom && !real_dual_sided && type != "curve" && type != "slope";total_studs_width = (stud_diameter * stud_rescale * real_width) + ((real_width - 1) * (stud_spacing - (stud_diameter * stud_rescale)));total_studs_length = (stud_diameter * stud_rescale * real_length) + ((real_length - 1) * (stud_spacing - (stud_diameter * stud_rescale)));total_posts_width = (post_diameter * (real_width - 1)) + ((real_width - 2) * (stud_spacing - post_diameter));total_posts_length = (post_diameter * (real_length - 1)) + ((real_length - 2) * (stud_spacing - post_diameter));total_axles_width = (axle_diameter * (real_width - 1)) + ((real_width - 2) * (stud_spacing - axle_diameter));total_axles_length = (axle_diameter * (real_length - 1)) + ((real_length - 2) * (stud_spacing - axle_diameter));total_pins_width = (pin_diameter * (real_width - 1)) + max(0, ((real_width - 2) * (stud_spacing - pin_diameter)));total_pins_length = (pin_diameter * (real_length - 1)) + max(0, ((real_length - 2) * (stud_spacing - pin_diameter)));overall_length = (real_length * stud_spacing) - (2 * wall_play);overall_width = (real_width * stud_spacing) - (2 * wall_play);wing_slope = (wing_type == "full" ?    ((real_width - (real_wing_end_width + 1)) / 2) / (real_length - (real_wing_base_length - 1))    :    (real_width - (real_wing_end_width)) / (real_length - (real_wing_base_length - 1)));

translate([-overall_length/2, -overall_width/2, 0]) // Comment to position at 0,0,0 instead of centered on X and Y.
union() {
difference() {
union() {
/**

• Include any union()s that should come before the final difference()s.
  */

              // The mass of the block.            difference() {                cube([overall_length, overall_width, real_height * block_height]);                translate([wall_thickness,wall_thickness,-roof_thickness]) cube([overall_length-wall_thickness*2,overall_width-wall_thickness*2,block_height*real_height]);            }            // The studs on top of the block (if it's not a tile).            if ( type != "tile" && !real_dual_bottom ) {                translate([stud_diameter * stud_rescale / 2, stud_diameter * stud_rescale / 2, 0])                 translate([(overall_length - total_studs_length)/2, (overall_width - total_studs_width)/2, 0]) {                    for (ycount=[0:real_width-1]) {                        for (xcount=[0:real_length-1]) {                            if (!skip_this_stud(xcount, ycount)) {                                translate([xcount*stud_spacing,ycount*stud_spacing,block_height*real_height]) stud();                            }                        }                    }               }            }            // Interior splines to catch the studs.            translate([stud_spacing / 2 - wall_play - (spline_thickness/2), 0, 0]) for (xcount = [0:real_length-1]) {                translate([0,wall_thickness,0]) translate([xcount * stud_spacing, 0, 0]) cube([spline_thickness, spline_length, real_height * block_height]);                translate([xcount * stud_spacing, overall_width - wall_thickness -  spline_length, 0]) cube([spline_thickness, spline_length, real_height * block_height]);            }            translate([0, stud_spacing / 2 - wall_play - (spline_thickness/2), 0]) for (ycount = [0:real_width-1]) {                translate([wall_thickness,0,0]) translate([0, ycount * stud_spacing, 0]) cube([spline_length, spline_thickness, real_height * block_height]);                translate([overall_length - wall_thickness -  spline_length, ycount * stud_spacing, 0]) cube([spline_length, spline_thickness, real_height * block_height]);            }            if (type != "baseplate" && real_width > 1 && real_length > 1 && !real_dual_sided && roof_thickness < block_height * height) {                // Reinforcements and posts                translate([post_diameter / 2, post_diameter / 2, 0]) {                    translate([(overall_length - total_posts_length)/2, (overall_width - total_posts_width)/2, 0]) {                        union() {                            // Posts                            for (ycount=[1:real_width-1]) {                                for (xcount=[1:real_length-1]) {                                    translate([(xcount-1)*stud_spacing,(ycount-1)*stud_spacing,0]) post(real_vertical_axle_holes && !skip_this_vertical_axle_hole(xcount, ycount));                                }                            }                            // Reinforcements                            if (real_reinforcement) {                                difference() {                                    for (ycount=[1:real_width-1]) {                                        for (xcount=[1:real_length-1]) {                                            translate([(xcount-1)*stud_spacing,(ycount-1)*stud_spacing,0]) reinforcement();                                        }                                    }                                    for (ycount=[1:real_width-1]) {                                        for (xcount=[1:real_length-1]) {                                            translate([(xcount-1)*stud_spacing,(ycount-1)*stud_spacing,-0.5]) cylinder(r=post_diameter/2-0.1, h=real_height*block_height+0.5, $fs=cylinder_precision);                                        }                                    }                                }                            }                        }                    }                }            }            if (type != "baseplate" && (real_width == 1 || real_length == 1) && real_width != real_length && !real_dual_sided && roof_thickness < block_height * height) {                // Pins                if (real_width == 1) {                    translate([(pin_diameter/2) + (overall_length - total_pins_length) / 2, overall_width/2, 0]) {                        for (xcount=[1:real_length-1]) {                            translate([(xcount-1)*stud_spacing,0,0]) cylinder(r=pin_diameter/2,h=block_height*real_height,$fs=cylinder_precision);                        }                    }                }                else {                    translate([overall_length/2, (pin_diameter/2) + (overall_width - total_pins_width) / 2, 0]) {                        for (ycount=[1:real_width-1]) {                            translate([0,(ycount-1)*stud_spacing,0]) cylinder(r=pin_diameter/2,h=block_height*real_height,$fs=cylinder_precision);                        }                    }                }            }            if (real_horizontal_holes) {                // The holes for the horizontal axles.                // 1-length bricks have the hole underneath the stud.                // >1-length bricks have the holes between the studs.                for (height_index = [0 : height - 1]) {                    translate([horizontal_holes_x_offset(), overall_width, height_index * block_height])                     translate([(overall_length - total_studs_length)/2, 0, 0]) {                    for (axle_hole_index=[horizontal_hole_start_index() : horizontal_hole_end_index()]) {                        if (!skip_this_horizontal_hole(axle_hole_index, height_index)) {                                translate([axle_hole_index*stud_spacing,0,horizontal_hole_z_offset]) rotate([90, 0, 0])  cylinder(r=horizontal_hole_diameter/2 + horizontal_hole_wall_thickness, h=overall_width,$fs=cylinder_precision);                            }                        }                    }                }            }        }        /**         * Include any differences from the basic brick here.         */        if (real_vertical_axle_holes) {            if (real_width > 1 && real_length > 1) {                translate([axle_diameter / 2, axle_diameter / 2, 0]) {                    translate([(overall_length - total_axles_length)/2, (overall_width - total_axles_width)/2, 0]) {                        for (ycount = [ 1 : real_width - 1 ]) {                            for (xcount = [ 1 : real_length - 1]) {                                if (!skip_this_vertical_axle_hole(xcount, ycount)) {                                    translate([(xcount-1)*stud_spacing,(ycount-1)*stud_spacing,-block_height/2]) axle();                                }                            }                        }                    }                }            }        }        if (type == "wing") {            if (wing_type == "full" || wing_type == "right")  {                translate([0, 0, -0.5]) linear_extrude(block_height * real_height + stud_height + 1) polygon(points=[                    [stud_spacing * (real_wing_base_length-1), -0.01],                    [overall_length + 0.01, -0.01],                    [overall_length + 0.01, (wing_type == "full" ?                        (overall_width / 2 - (real_wing_end_width * stud_spacing / 2))                        :                        (overall_width - (real_wing_end_width * stud_spacing))                    )]                ]                );            }            if (wing_type == "full" || wing_type == "left")  {                translate([0, 0, -0.5]) linear_extrude(block_height * real_height + stud_height + 1) polygon(points=[                    [stud_spacing * (real_wing_base_length-1), overall_width + 0.01],                    [overall_length + 0.01, overall_width + 0.01],                    [overall_length + 0.01, (wing_type == "full" ? overall_width / 2 : 0) + (real_wing_end_width * stud_spacing / (wing_type == "full" ? 2 : 1))]                ]                );            }        }        else if (type == "slope") {            translate([0, overall_width+0.5, 0]) rotate([90, 0, 0]) linear_extrude(overall_width+1) polygon(points=[                [-0.1, (block_height * real_slope_end_height) + stud_height],                [min(overall_length, overall_length - (stud_spacing * real_slope_stud_rows) + (wall_play/2)), real_height * block_height - roof_thickness],                [min(overall_length, overall_length - (stud_spacing * real_slope_stud_rows) + (wall_play/2)), real_height * block_height + stud_height + 1],                [-0.1, real_height * block_height + stud_height + 1]            ]);        }        else if (type == "curve") {            if (real_curve_type == "concave") {                                    echo(curve_circle_height());                difference() {                    translate([                            -curve_circle_length() / 2, // Align the center of the cube with the end of the block.                            -0.5, // Center the extra width on the block.                            (real_height * block_height) - (curve_circle_height() / 2)  // Align the bottom of the cube with the center of the curve circle.                        ])                        cube([curve_circle_length(), overall_width + 1, curve_circle_height()]);                    translate([                            curve_circle_length() / 2,  // Align the end of the curve with the end of the block.                            overall_width / 2, // Center it on the block.                            (real_height * block_height) - (curve_circle_height() / 2)  // Align the top of the curve with the top of the block.                        ])                        rotate([90, 0, 0]) // Rotate sideways                        translate([0, 0, -overall_width/2]) // Move so the cylinder is z-centered.                        resize([curve_circle_length(), curve_circle_height(), 0]) // Resize to the approprate scale.                        cylinder(r=real_height * block_height, h=overall_width, $fs=cylinder_precision);                }            }            else if (real_curve_type == "convex") {                union() {                    translate([0, 0, real_height * block_height]) cube([overall_length - (real_curve_stud_rows * stud_spacing), overall_width, stud_height + .1]);                    translate([0, 0, block_height * real_height])                        translate([0, (overall_width+1)/2-.5, 0]) // Center across the end of the block.                        rotate([90, 0, 0])                        translate([0, 0, -((overall_width+1)/2)]) // z-center                        resize([curve_circle_length(), curve_circle_height(), 0]) // Resize to the final dimensions.                        cylinder(r=block_height * real_height, h=overall_width+1, $fs=cylinder_precision);                }            }        }        else if (type == "baseplate") {            // Rounded corners.            union() {                translate([overall_length, overall_width, 0]) translate([-((stud_spacing / 2) - wall_play), -((stud_spacing / 2) - wall_play), 0]) negative_rounded_corner(r=((stud_spacing / 2) - wall_play), h=real_height * block_height);                translate([0, overall_width, 0]) translate([((stud_spacing / 2) - wall_play), -((stud_spacing / 2) - wall_play), 0]) rotate([0, 0, 90]) negative_rounded_corner(r=((stud_spacing / 2) - wall_play), h=real_height * block_height);                translate([((stud_spacing / 2) - wall_play), ((stud_spacing / 2) - wall_play), 0]) rotate([0, 0, 180]) negative_rounded_corner(r=((stud_spacing / 2) - wall_play), h=real_height * block_height);                translate([overall_length, 0, 0]) translate([-((stud_spacing / 2) - wall_play), ((stud_spacing / 2) - wall_play), 0]) rotate([0, 0, 270]) negative_rounded_corner(r=((stud_spacing / 2) - wall_play), h=real_height * block_height);            }        }        if (real_horizontal_holes) {            // The holes for the horizontal axles.            // 1-length bricks have the hole underneath the stud.            // >1-length bricks have the holes between the studs.            for (height_index = [0 : height - 1]) {                translate([horizontal_holes_x_offset(), 0, height_index * block_height])                 translate([(overall_length - total_studs_length)/2, 0, 0]) {                    for (axle_hole_index=[horizontal_hole_start_index() : horizontal_hole_end_index()]) {                        if (!skip_this_horizontal_hole(axle_hole_index, height_index)) {                            union() {                                translate([axle_hole_index*stud_spacing,overall_width,horizontal_hole_z_offset]) rotate([90, 0, 0])  cylinder(r=horizontal_hole_diameter/2, h=overall_width,$fs=cylinder_precision);                                // Bevels. The +/- 0.1 measurements are here just for nicer previews in OpenSCAD, and could be removed.                                translate([axle_hole_index*stud_spacing,horizontal_hole_bevel_depth-0.1,horizontal_hole_z_offset]) rotate([90, 0, 0]) cylinder(r=horizontal_hole_bevel_diameter/2, h=horizontal_hole_bevel_depth+0.1,$fs=cylinder_precision);                                translate([axle_hole_index*stud_spacing,overall_width+0.1,horizontal_hole_z_offset]) rotate([90, 0, 0]) cylinder(r=horizontal_hole_bevel_diameter/2, h=horizontal_hole_bevel_depth+0.1,$fs=cylinder_precision);                            }                        }                    }                }            }        }    }    /**     * Any final union()s for the brick.     */    if (type == "wing") {        difference() {            union() {                if ( wing_type == "full" || wing_type == "right" ){                    linear_extrude(block_height * real_height) polygon(points=[                        [stud_spacing * (real_wing_base_length-1), 0],                        [overall_length, (wing_type == "full" ?                             ((overall_width / 2) - (real_wing_end_width * stud_spacing / 2))                            :                            (overall_width - (real_wing_end_width * stud_spacing))                        )],                        [overall_length, (wing_type == "full" ?                             ((overall_width / 2) - (real_wing_end_width * stud_spacing / 2))                            :                            (overall_width - (real_wing_end_width * stud_spacing))                        ) + wall_thickness],                        [stud_spacing * (real_wing_base_length-1), wall_thickness]                    ]);                }                if (wing_type == "full" || wing_type == "left") {                    linear_extrude(block_height * real_height) polygon(points=[                        [stud_spacing * (real_wing_base_length-1), overall_width],                        [overall_length, (wing_type == "full" ? overall_width / 2 : 0) + (real_wing_end_width * stud_spacing / (wing_type == "full" ? 2 : 1))],                        [overall_length, (wing_type == "full" ? overall_width / 2 : 0) + (real_wing_end_width * stud_spacing / (wing_type == "full" ? 2 : 1)) - wall_thickness],                        [stud_spacing * (real_wing_base_length-1), overall_width - wall_thickness]                    ]);                }            }            if (real_stud_notches) {                translate([overall_length/2, overall_width/2, 0])                    translate([0, 0, -(1/3 * block_height)]) block(                        width=real_width,                        length=real_length,                        height=1/3,                        brand=brand,                        stud_type="solid",                        type="brick",                        stud_rescale=1.5                    );            }        }    }    else if (type == "slope") {        translate([0, overall_width, 0]) rotate([90, 0, 0]) linear_extrude(overall_width) polygon(points=[            [0, (block_height * real_slope_end_height) + stud_height],            [0, (block_height * real_slope_end_height) + stud_height + roof_thickness],            [min(overall_length, overall_length - (stud_spacing * real_slope_stud_rows) + (wall_play/2)), real_height * block_height],            [min(overall_length, overall_length - (stud_spacing * real_slope_stud_rows) + (wall_play/2)), (real_height * block_height) - roof_thickness]        ]);    }    else if (type == "curve") {        if (real_curve_type == "concave") {            intersection() {                translate([                        -curve_circle_length() / 2, // Align the center of the cube with the end of the block.                        -0.5, // Center the extra width on the block.                        (real_height * block_height) - (curve_circle_height() / 2)  // Align the bottom of the cube with the center of the curve circle.                    ])                    cube([curve_circle_length(), overall_width + 1, curve_circle_height()]);                difference() {                       translate([                            curve_circle_length() / 2,  // Align the end of the curve with the end of the block.                            overall_width / 2, // Center it on the block.                            (real_height * block_height) - (curve_circle_height() / 2)  // Align the top of the curve with the top of the block.                        ])                        rotate([90, 0, 0]) // Rotate sideways                        translate([0, 0, -overall_width/2]) // Move so the cylinder is z-centered.                        resize([curve_circle_length(), curve_circle_height(), 0]) // Resize to the approprate scale.                        cylinder(r=real_height * block_height, h=overall_width, $fs=cylinder_precision);                    translate([                            curve_circle_length() / 2,  // Align the end of the curve with the end of the block.                            overall_width / 2, // Center it on the block.                            (real_height * block_height) - (curve_circle_height() / 2) // Align the top of the curve with the top of the block.                        ])                        rotate([90, 0, 0]) // Rotate sideways                        translate([0, 0, -overall_width/2]) // Move so the cylinder is z-centered.                        resize([curve_circle_length() - (wall_thickness * 2), curve_circle_height() - (wall_thickness * 2), 0]) // Resize to the approprate scale.                        cylinder(r=real_height * block_height, h=overall_width, $fs=cylinder_precision);                }            }        }        else if (real_curve_type == "convex") {            intersection() {                translate([                    0,                    0,                    (real_height * block_height) - (curve_circle_height() / 2) - wall_thickness // Align the top of the cube with the top of the block.                ])                    cube([curve_circle_length() / 2, overall_width, curve_circle_height() / 2 + wall_thickness]);               translate([0, 0, block_height * real_height])                    translate([0, overall_width/2, 0]) // Center across the end of the block.                    rotate([90, 0, 0])                    translate([0, 0, -overall_width/2]) // z-center                    difference() {                        resize([curve_circle_length() + (wall_thickness * 2), curve_circle_height() + (wall_thickness * 2), 0]) // Resize to the final dimensions.                        cylinder(r=block_height * real_height, h=overall_width, $fs=cylinder_precision);                        translate([0, 0, -0.5]) // The inner cylinder is just a little taller, for nicer OpenSCAD previews.                            resize([curve_circle_length(), curve_circle_height(), 0]) // Resize to the final dimensions.                            cylinder(r=block_height * real_height, h=overall_width+1, $fs=cylinder_precision);                    }            }        }    }    if (real_dual_sided) {        translate([overall_length/2, overall_width/2, block_height * height]) mirror([0,0,1]) block(            width=real_width,            length=real_length,            height=real_height,            type=type,            brand=brand,            stud_type=stud_type,            horizontal_holes=real_horizontal_holes,            vertical_axle_holes=real_vertical_axle_holes,            reinforcement=real_reinforcement,            wing_type=wing_type,            wing_end_width=real_wing_end_width,            wing_base_length=real_wing_base_length-1,            stud_notches=real_stud_notches,            slope_stud_rows=real_slope_stud_rows,            slope_end_height=real_slope_end_height,            curve_stud_rows=real_curve_stud_rows,            curve_type=real_curve_type,            curve_end_height=real_curve_end_height,            roadway_width=real_roadway_width,            roadway_length=real_roadway_length,            roadway_x=real_roadway_x,            roadway_y=real_roadway_y,            stud_rescale=stud_rescale,            dual_sided=false        );    }    if (real_dual_bottom) {        translate([overall_length/2, overall_width/2, block_height * height * 2]) mirror([0,0,1]) block(            width=real_width,            length=real_length,            height=real_height,            type="tile",            brand=brand,            stud_type=stud_type,            horizontal_holes=real_horizontal_holes,            vertical_axle_holes=real_vertical_axle_holes,            reinforcement=real_reinforcement,            wing_type=wing_type,            wing_end_width=real_wing_end_width,            wing_base_length=real_wing_base_length-1,            stud_notches=real_stud_notches,            slope_stud_rows=real_slope_stud_rows,            slope_end_height=real_slope_end_height,            curve_stud_rows=real_curve_stud_rows,            curve_type=real_curve_type,            curve_end_height=real_curve_end_height,            roadway_width=real_roadway_width,            roadway_length=real_roadway_length,            roadway_x=real_roadway_x,            roadway_y=real_roadway_y,            stud_rescale=stud_rescale,            dual_sided=false,            dual_bottom=false        );    }

  }

  module post(vertical_axle_hole) {
  difference() {
  cylinder(r=post_diameter/2, h=real_heightblock_height,$fs=cylinder_precision);
  if (vertical_axle_hole==true) {
  translate([0,0,-block_height/2])
  axle();
  } else {
  translate([0,0,-0.5]) cylinder(r=(post_diameter/2)-post_wall_thickness, h=real_heightblock_height+1,$fs=cylinder_precision);
  }
  }
  }

  module reinforcement() {
  union() {
  translate([0,0,real_heightblock_height/2]) union() {
  cube([reinforcing_width, 2 (stud_spacing - (2 wall_play)), real_height block_height],center=true);
  rotate(v=[0,0,1],a=90) cube([reinforcing_width, 2 (stud_spacing - (2 wall_play)), real_height * block_height], center=true);
  }
  }
  }

  module axle() {
  translate([0,0,(real_height+1)block_height/2]) union() {
  cube([axle_diameter,axle_spline_width,(real_height+1)block_height],center=true);
  cube([axle_spline_width,axle_diameter,(real_height+1)*block_height],center=true);
  }
  }

  module stud() {
  difference() {
  cylinder(r=(stud_diameter*stud_rescale)/2,h=stud_height,$fs=cylinder_precision);

      if (stud_type == "hollow") {        // 0.5 is for cleaner preview; doesn't affect functionality.        cylinder(r=(hollow_stud_inner_diameter*stud_rescale)/2,h=stud_height+0.5,$fs=cylinder_precision);    }}

  }

  function curve_circle_length() = (overall_length - (stud_spacing min(real_length - 1, real_curve_stud_rows)) + (wall_play/2)) 2;
  function curve_circle_height() = (
  (
  (block_height real_height) - (real_curve_end_height block_height)) 2) - (real_curve_type == "convex" ? (stud_height 2) + (wall_thickness * 2) : 0);

  function wing_width(x_pos) = (real_width - width_loss(x_pos));

  function width_loss(x_pos) = (type != "wing" ? 0 :
  round((wing_type == "full" ?
  max(0, (2 wing_slope (x_pos - (real_wing_base_length - 1)))) + 0.3 // Full wing
  :
  max(0, (wing_slope * (x_pos - (real_wing_base_length - 1)))) + 0.2 // Half wing
  )) // +extra is because full studs can still fit on partially missing bases, but not by much
  );

  function horizontal_hole_start_index() = ( ( (type == "slope" && real_slope_stud_rows == 1)		(type == "curve" && real_curve_stud_rows == 1) ) ? real_length - 1

  0

  ); function horizontal_hole_end_index() = ( ( real_length == 1		(type == "slope" && real_slope_stud_rows == 1)		(type == "curve" && real_curve_stud_rows == 1) ) ? real_length - 1

  real_length - 2

  );
  function skip_this_horizontal_hole(xcount, zcount) = (
  (type == "slope" && ((zcount >= slope_end_height) && (xcount <= real_length - real_slope_stud_rows - 1)))
  ||
  (type == "curve" && ((zcount >= curve_end_height) && (xcount <= real_length - real_curve_stud_rows - 1)))
  );

  function horizontal_holes_x_offset() = (
  (horizontal_hole_diameter / 2)

  • ( ( real_length == 1		(type == "slope" && real_slope_stud_rows == 1)		(type == "curve" && real_curve_stud_rows == 1) ) ? 0

    (stud_spacing / 2)

    )
    );

  function put_stud_here(xcount, ycount) = ( (type != "wing" && real_roadway_width > 0 && real_roadway_length > 0)		(type == "wing" && ( (wing_type == "full" && (ycount+1 > ceil(width_loss(xcount+1)/2)) && (ycount+1 <= floor(real_width - (width_loss(xcount+1)/2))))		(wing_type == "left" && ycount+1 <= wing_width(xcount+1))		(wing_type == "right" && ycount >= width_loss(xcount+1)) ) )

  (real_roadway_width == 0 && real_roadway_length == 0)||(!pos_in_roadway(xcount, ycount))

  );

  function put_vertical_axle_hole_here(xcount, ycount) = (
  !skip_this_axle_hole(xcount, ycount)
  );

  function skip_this_vertical_axle_hole(xcount, ycount) = (
  (type == "slope" && xcount < (real_length - real_slope_stud_rows + 1))
  ||
  (type == "curve" && xcount < (real_length - real_curve_stud_rows + 1))

  );

  function skip_this_stud(xcount, ycount) = ( (type == "wing" && ( (wing_type == "full" && ((ycount+1 <= ceil(width_loss(xcount+1)/2))		(ycount+1 > floor(real_width - (width_loss(xcount+1)/2)))))		(wing_type == "left" && ycount+1 > wing_width(xcount+1))		(wing_type == "right" && ycount < width_loss(xcount+1)) ) )

  (real_roadway_width > 0 && real_roadway_length > 0 && pos_in_roadway(xcount, ycount))

  );

  function pos_in_roadway(x, y) = (
  x >= real_roadway_x
  && y >= real_roadway_y
  && y < real_roadway_y + real_roadway_width
  && x < real_roadway_x + real_roadway_length
  );

  module negative_rounded_corner(r,h) {
  difference() {
  translate([0, 0, -.5]) cube([r+1, r+1, h+1]);
  translate([0, 0, -1]) cylinder(r=r, h=h + 2, $fs=cylinder_precision);
  }
  }
  }

module uncenter(width, length, height) {
// stud_spacing = 8
// wall_play = 0.1
translate([((8 length) / 2) - 0.1, ((8 width) / 2) - 0.1, height ? ((8 * height) / 2) - 0.1 : 0]) children();
}

module place(x, y, z=0) {
translate([8 y, 8 x, z * 9.6]) children();
}