1 partitions.scad

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Table of Contents

• LibFile: partitions.scad
• File Contents
• Section: Planar Cutting
• Function/Module: half_of()
• Function/Module: left_half()
• Function/Module: right_half()
• Function/Module: front_half()
• Function/Module: back_half()
• Function/Module: bottom_half()
• Function/Module: top_half()
• Section: Partioning into Interlocking Pieces
• Module: partition_mask()
• Module: partition_cut_mask()
• Module: partition()

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LibFile: partitions.scad

Cut objects with a plane, or partition them into interlocking pieces for easy printing of large objects.

To use, add the following lines to the beginning of your file:

include <BOSL2/std.scad>

File Contents

1. Section: Planar Cutting

   • half_of() – Masks half of an object at a cut plane. ^{[Geom] [VNF] [Path] [Region]}
   • left_half() – Masks the right half of an object along the Y-Z plane, leaving the left half. ^{[Geom] [VNF] [Path] [Region]}
   • right_half() – Masks the left half of an object along the Y-Z plane, leaving the right half. ^{[Geom] [VNF] [Path] [Region]}
   • front_half() – Masks the back half of an object along the X-Z plane, leaving the front half. ^{[Geom] [VNF] [Path] [Region]}
   • back_half() – Masks the front half of an object along the X-Z plane, leaving the back half. ^{[Geom] [VNF] [Path] [Region]}
   • bottom_half() – Masks the top half of an object along the X-Y plane, leaving the bottom half. ^{[Geom] [VNF] [Path] [Region]}
   • top_half() – Masks the bottom half of an object along the X-Y plane, leaving the top half. ^{[Geom] [VNF] [Path] [Region]}

2. Section: Partioning into Interlocking Pieces

   • partition_mask() – Creates a mask to remove half an object with the remaining half suitable for reassembly. ^[Geom]
   • partition_cut_mask() – Creates a mask to cut an object into two subparts that can be reassembled. ^[Geom]
   • partition() – Cuts an object in two with matched joining edges, then separates the parts. ^{[Geom] [VNF] [Path] [Region]}

Section: Planar Cutting

Function/Module: half_of()

Synopsis: Masks half of an object at a cut plane. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), front_half(), left_half(), right_half(), top_half(), bottom_half(), intersection()

Usage: as module

• half_of(v, [cp], [s], [planar]) CHILDREN;

Usage: as function

• result = half_of(p,v,[cp]);

Description:

Slices an object at a cut plane, and masks away everything that is on one side. The v parameter is either a plane specification or a normal vector. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model. When called as a function, you must supply a vnf, path or region in p. If planar is set to true for the module version the operation is performed in 2D and UP and DOWN are treated as equivalent to BACK and FWD respectively.

Arguments:

By Position	What it does
p	path, region or VNF to slice. (Function version)
v	Normal of plane to slice at. Keeps everything on the side the normal points to. Default: [0,0,1] (UP)
cp	If given as a scalar, moves the cut plane along the normal by the given amount. If given as a point, specifies a point on the cut plane. Default: [0,0,0]
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
planar	If true, perform a 2D operation. When planar, a v of UP or DOWN becomes equivalent of BACK and FWD respectively. (Module version). Default: false.

Example 1:

include <BOSL2/std.scad>
half_of(DOWN+BACK, cp=[0,-10,0]) cylinder(h=40, r1=10, r2=0, center=false);

Example 2:

include <BOSL2/std.scad>
half_of(DOWN+LEFT, s=200) sphere(d=150);

Example 3:

include <BOSL2/std.scad>
half_of([1,1], planar=true) circle(d=50);

---

Function/Module: left_half()

Synopsis: Masks the right half of an object along the Y-Z plane, leaving the left half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), front_half(), right_half(), top_half(), bottom_half(), half_of(), intersection()

Usage: as module

• left_half([s], [x]) CHILDREN;
• left_half(planar=true, [s], [x]) CHILDREN;

Usage: as function

• result = left_half(p, [x]);

Description:

Slices an object at a vertical Y-Z cut plane, and masks away everything that is right of it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
x	The X coordinate of the cut-plane. Default: 0
planar	If true, perform a 2D operation. (Module version) Default: false.

Example 1:

include <BOSL2/std.scad>
left_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
left_half(x=-8) sphere(r=20);

Example 3:

include <BOSL2/std.scad>
left_half(planar=true) circle(r=20);

---

Function/Module: right_half()

Synopsis: Masks the left half of an object along the Y-Z plane, leaving the right half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), front_half(), left_half(), top_half(), bottom_half(), half_of(), intersection()

Usage: as module

• right_half([s=], [x=]) CHILDREN;
• right_half(planar=true, [s=], [x=]) CHILDREN;

Usage: as function

• result = right_half(p, [x=]);

Description:

Slices an object at a vertical Y-Z cut plane, and masks away everything that is left of it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
x	The X coordinate of the cut-plane. Default: 0
planar	If true, perform a 2D operation. (Module version) Default: false.

Example 1:

include <BOSL2/std.scad>
right_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
right_half(x=-5) sphere(r=20);

Example 3:

include <BOSL2/std.scad>
right_half(planar=true) circle(r=20);

---

Function/Module: front_half()

Synopsis: Masks the back half of an object along the X-Z plane, leaving the front half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), left_half(), right_half(), top_half(), bottom_half(), half_of(), intersection()

Usage:

• front_half([s], [y]) CHILDREN;
• front_half(planar=true, [s], [y]) CHILDREN;

Usage: as function

• result = front_half(p, [y]);

Description:

Slices an object at a vertical X-Z cut plane, and masks away everything that is behind it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
y	The Y coordinate of the cut-plane. Default: 0
planar	If true, perform a 2D operation. (Module version) Default: false.

Example 1:

include <BOSL2/std.scad>
front_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
front_half(y=5) sphere(r=20);

Example 3:

include <BOSL2/std.scad>
front_half(planar=true) circle(r=20);

---

Function/Module: back_half()

Synopsis: Masks the front half of an object along the X-Z plane, leaving the back half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: front_half(), left_half(), right_half(), top_half(), bottom_half(), half_of(), intersection()

Usage:

• back_half([s], [y]) CHILDREN;
• back_half(planar=true, [s], [y]) CHILDREN;

Usage: as function

• result = back_half(p, [y]);

Description:

Slices an object at a vertical X-Z cut plane, and masks away everything that is in front of it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
y	The Y coordinate of the cut-plane. Default: 0
planar	If true, perform a 2D operation. (Module version) Default: false.

Example 1:

include <BOSL2/std.scad>
back_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
back_half(y=8) sphere(r=20);

Example 3:

include <BOSL2/std.scad>
back_half(planar=true) circle(r=20);

---

Function/Module: bottom_half()

Synopsis: Masks the top half of an object along the X-Y plane, leaving the bottom half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), front_half(), left_half(), right_half(), top_half(), half_of(), intersection()

Usage:

• bottom_half([s], [z]) CHILDREN;

Usage: as function

• result = bottom_half(p, [z]);

Description:

Slices an object at a horizontal X-Y cut plane, and masks away everything that is above it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
z	The Z coordinate of the cut-plane. Default: 0

Example 1:

include <BOSL2/std.scad>
bottom_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
bottom_half(z=-10) sphere(r=20);

---

Function/Module: top_half()

Synopsis: Masks the bottom half of an object along the X-Y plane, leaving the top half. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking

See Also: back_half(), front_half(), left_half(), right_half(), bottom_half(), half_of(), intersection()

Usage: as module

• top_half([s], [z]) CHILDREN;

Usage: as function

• result = top_half(p, [z]);

Description:

Slices an object at a horizontal X-Y cut plane, and masks away everything that is below it. The s parameter is needed for the module version to control the size of the masking cube. If s is too large then the preview display will flip around and display the wrong half, but if it is too small it won't fully mask your model.

Arguments:

By Position	What it does
p	VNF, region or path to slice (function version)
s	Mask size to use. Use a number larger than twice your object's largest axis. If you make this too large, OpenSCAD's preview rendering may display the wrong half. (Module version) Default: 100
z	The Z coordinate of the cut-plane. Default: 0

Example 1:

include <BOSL2/std.scad>
top_half() sphere(r=20);

Example 2:

include <BOSL2/std.scad>
top_half(z=5) sphere(r=20);

---

Section: Partioning into Interlocking Pieces

Module: partition_mask()

Synopsis: Creates a mask to remove half an object with the remaining half suitable for reassembly. ^[Geom]

Topics: Partitions, Masking, Paths

See Also: partition_cut_mask(), partition()

Usage:

• partition_mask(l, w, h, [cutsize], [cutpath], [gap], [inverse], [$slop=], [anchor=], [spin=], [orient=]) [ATTACHMENTS];

Description:

Creates a mask that you can use to difference or intersect with an object to remove half of it, leaving behind a side designed to allow assembly of the sub-parts.

Arguments:

By Position	What it does
l	The length of the cut axis.
w	The width of the part to be masked, back from the cut plane.
h	The height of the part to be masked.
cutsize	The width of the cut pattern to be used.
cutpath	The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5.
gap	Empty gaps between cutpath iterations. Default: 0
inverse	If true, create a cutpath that is meant to mate to a non-inverted cutpath.
spin	Rotate this many degrees around the Z axis. See spin. Default: 0
orient	Vector to rotate top towards. See orient. Default: UP
$slop	The amount to shrink the mask by, to correct for printer-specific fitting.

Example 1:

include <BOSL2/std.scad>
partition_mask(w=50, gap=0, cutpath="jigsaw");

Example 2:

include <BOSL2/std.scad>
partition_mask(w=50, gap=30, cutpath="jigsaw");

Example 3:

include <BOSL2/std.scad>
partition_mask(w=50, gap=30, cutpath="jigsaw", inverse=true);

Example 4:

include <BOSL2/std.scad>
partition_mask(w=50, gap=30, cutsize=15, cutpath="jigsaw");

Example 5:

include <BOSL2/std.scad>
partition_mask(w=50, cutsize=[20,20], gap=30, cutpath="jigsaw");

Example 6:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="sawtooth");

Example 7:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="sinewave");

Example 8:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="comb");

Example 9:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="finger");

Example 10:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="dovetail");

Example 11:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="hammerhead");

Example 12:

include <BOSL2/std.scad>
partition_mask(w=20, cutpath="jigsaw");

---

Module: partition_cut_mask()

Synopsis: Creates a mask to cut an object into two subparts that can be reassembled. ^[Geom]

Topics: Partitions, Masking, Paths

See Also: partition_mask(), partition()

Usage:

• partition_cut_mask(l, [cutsize], [cutpath], [gap], [inverse], [$slop=], [anchor=], [spin=], [orient=]) [ATTACHMENTS];

Description:

Creates a mask that you can use to difference with an object to cut it into two sub-parts that can be assembled. The $slop value is important to get the proper fit and should probably be smaller than 0.2. The examples below use larger values to make the mask easier to see.

Arguments:

By Position	What it does
l	The length of the cut axis.
h	The height of the part to be masked.
cutsize	The width of the cut pattern to be used. Default: 10
cutpath	The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5. Default: "jigsaw"
gap	Empty gaps between cutpath iterations. Default: 0
spin	Rotate this many degrees around the Z axis. See spin. Default: 0
orient	Vector to rotate top towards. See orient. Default: UP
$slop	The width of the cut mask, to correct for printer-specific fitting.

Example 1:

include <BOSL2/std.scad>
partition_cut_mask(gap=0, cutpath="dovetail");

Example 2:

include <BOSL2/std.scad>
partition_cut_mask(gap=30, cutpath="dovetail");

Example 3:

include <BOSL2/std.scad>
partition_cut_mask(gap=30, cutsize=15, cutpath="dovetail");

Example 4:

include <BOSL2/std.scad>
partition_cut_mask(gap=30, cutsize=[20,20], cutpath="dovetail");

Example 5:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="sawtooth",$slop=0.5);

Example 6:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="sinewave",$slop=0.5);

Example 7:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="comb",$slop=0.5);

Example 8:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="finger",$slop=0.5);

Example 9:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="dovetail",$slop=1);

Example 10:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="hammerhead",$slop=1);

Example 11:

include <BOSL2/std.scad>
partition_cut_mask(cutpath="jigsaw",$slop=0.5);

---

Module: partition()

Synopsis: Cuts an object in two with matched joining edges, then separates the parts. ^{[Geom] [VNF] [Path] [Region]}

Topics: Partitions, Masking, Paths

See Also: partition_cut_mask(), partition_mask()

Usage:

• partition(size, [spread], [cutsize], [cutpath], [gap], [spin], [$slop=]) CHILDREN;

Description:

Partitions an object into two parts, spread apart a small distance, with matched joining edges.

Arguments:

By Position	What it does
size	The [X,Y,Z] size of the object to partition.
spread	The distance to spread the two parts by.
cutsize	The width of the cut pattern to be used.
cutpath	The cutpath to use. Standard named paths are "flat", "sawtooth", "sinewave", "comb", "finger", "dovetail", "hammerhead", and "jigsaw". Alternatively, you can give a cutpath as a 2D path, where X is between 0 and 1, and Y is between -0.5 and 0.5.
gap	Empty gaps between cutpath iterations. Default: 0
spin	Rotate this many degrees around the Z axis. See spin. Default: 0

By Name	What it does
$slop	Extra gap to leave to correct for printer-specific fitting.

Side Effects:

• $idx is set to 0 on the back part and 1 on the front part.

Example 1:

include <BOSL2/std.scad>
partition(spread=12, cutpath="dovetail") cylinder(h=50, d=80, center=false);

Example 2:

include <BOSL2/std.scad>
partition(spread=12, gap=30, cutpath="dovetail") cylinder(h=50, d=80, center=false);

Example 3:

include <BOSL2/std.scad>
partition(spread=20, gap=20, cutsize=15, cutpath="dovetail") cylinder(h=50, d=80, center=false);

Example 4:

include <BOSL2/std.scad>
partition(spread=25, gap=15, cutsize=[20,20], cutpath="dovetail") cylinder(h=50, d=80, center=false);

Example 5:

include <BOSL2/std.scad>
partition(cutpath="sawtooth") cylinder(h=50, d=80, center=false);

Example 6:

include <BOSL2/std.scad>
partition(cutpath="sinewave") cylinder(h=50, d=80, center=false);

Example 7:

include <BOSL2/std.scad>
partition(cutpath="comb") cylinder(h=50, d=80, center=false);

Example 8:

include <BOSL2/std.scad>
partition(cutpath="finger") cylinder(h=50, d=80, center=false);

Example 9:

include <BOSL2/std.scad>
partition(spread=12, cutpath="dovetail") cylinder(h=50, d=80, center=false);

Example 10:

include <BOSL2/std.scad>
partition(spread=12, cutpath="hammerhead") cylinder(h=50, d=80, center=false);

Example 11:

include <BOSL2/std.scad>
partition(cutpath="jigsaw") cylinder(h=50, d=80, center=false);

---

Indices

Table of Contents
Function Index
Topics Index
Cheat Sheet
Tutorials

List of Files:

Basic Modeling:

• constants.scad ^STD
• transforms.scad ^STD
• attachments.scad ^STD
• shapes2d.scad ^STD
• shapes3d.scad ^STD
• drawing.scad ^STD
• masks2d.scad ^STD
• masks3d.scad ^STD
• distributors.scad ^STD
• color.scad ^STD
• partitions.scad ^STD
• miscellaneous.scad ^STD

Advanced Modeling:

• paths.scad ^STD
• regions.scad ^STD
• skin.scad ^STD
• vnf.scad ^STD
• beziers.scad
• nurbs.scad
• rounding.scad
• turtle3d.scad

Math:

• math.scad ^STD
• linalg.scad ^STD
• vectors.scad ^STD
• coords.scad ^STD
• geometry.scad ^STD
• trigonometry.scad ^STD

Data Management:

• version.scad ^STD
• comparisons.scad ^STD
• lists.scad ^STD
• utility.scad ^STD
• strings.scad ^STD
• structs.scad ^STD
• fnliterals.scad

Threaded Parts:

• threading.scad
• screws.scad
• screw_drive.scad
• bottlecaps.scad

Parts:

• ball_bearings.scad
• cubetruss.scad
• gears.scad
• hinges.scad
• joiners.scad
• linear_bearings.scad
• modular_hose.scad
• nema_steppers.scad
• polyhedra.scad
• sliders.scad
• tripod_mounts.scad
• walls.scad
• wiring.scad

Footnotes:

STD = Included in std.scad

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