From eb12f5f9cb1581dcfb99fd3d7fd4e79dd1910b08 Mon Sep 17 00:00:00 2001 From: Garth Minette Date: Mon, 28 Dec 2020 02:10:50 -0800 Subject: [PATCH] Tutorials work.. Shapes2d and Paths. --- tutorials/Paths.md | 504 +++++++++++++++++++ tutorials/Shapes2d.md | 553 +++++++++++++++++++++ tutorials/{Basic_Shapes.md => Shapes3d.md} | 241 +-------- version.scad | 2 +- 4 files changed, 1073 insertions(+), 227 deletions(-) create mode 100644 tutorials/Paths.md create mode 100644 tutorials/Shapes2d.md rename tutorials/{Basic_Shapes.md => Shapes3d.md} (55%) diff --git a/tutorials/Paths.md b/tutorials/Paths.md new file mode 100644 index 0000000..68e5421 --- /dev/null +++ b/tutorials/Paths.md @@ -0,0 +1,504 @@ +# Paths, Polygons and Regions Tutorial + +## Paths +A number of advanced features in BOSL2 rely on paths, which are just ordered lists of points. + +First-off, some terminology: +- A 2D point is a vectors of X and Y axis position values ie: `[3,4]` or `[7,-3]`. +- A 3D point is a vectors of X, Y and Z axis position values ie: `[3,4,2]` or `[-7,5,3]`. +- A 2D path is simply a list of two or more 2D points. ie: `[[5,7], [1,-5], [-5,6]]` +- A 3D path is simply a list of two or more 3D points. ie: `[[5,7,-1], [1,-5,3], [-5,6,1]]` +- A polygon is a 2D (or planar 3D) path where the last point is assumed to connect to the first point. +- A region is a list of 2D polygons, where each polygon is XORed against all the others. ie: if one polygon is inside another, it makes a hole in the first polygon. + +### Stroke +A path can be hard to visualize, since it's just a bunch of numbers in the source code. +One way to see the path is to pass it to `polygon()`: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + polygon(path); +``` + +Sometimes, however, it's easier to see just the path itself. For this, you can use the `stroke()` module. +At its most basic, `stroke()` just shows the path's line segments: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path); +``` + +You can vary the width of the drawn path with the `width=` argument: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, width=3); +``` + +You can vary the line length along the path by giving a list of widths, one per point: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, width=[3,2,1,2,3]); +``` + +If a path is meant to represent a closed polygon, you can use `closed=true` to show it that way: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, closed=true); +``` + +The ends of the drawn path are normally capped with a "round" endcap, but there are other options: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcaps="round"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcaps="butt"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcaps="line"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcaps="tail"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcaps="arrow2"); +``` + +For more standard supported endcap options, see the docs for [`stroke()`](shapes2d.scad#stroke). + +The start and ending endcaps can be specified individually or separately, using `endcap1=` and `endcap2=`: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcap1="butt", endcap2="arrow2"); +``` + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + stroke(path, endcap1="tail", endcap2="arrow"); +``` + +The size of the endcaps will be relative to the width of the line where the endcap is to be placed: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + widths = [1, 1.25, 1.5, 1.75, 2]; + stroke(path, width=widths, endcaps="arrow2"); +``` + +If none of the standard endcaps are useful to you, it is possible to design your own, simply by +passing a path to the `endcaps=`, `endcap1=`, or `endcap2=` arguments. You may also need to give +`trim=` to tell it how far back to trim the main line, so it renders nicely. The values in the +endcap polygon, and in the `trim=` argument are relative to the line width. A value of 1 is one +line width size. + +Untrimmed: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + dblarrow = [[0,0], [2,-3], [0.5,-2.3], [2,-4], [0.5,-3.5], [-0.5,-3.5], [-2,-4], [-0.5,-2.3], [-2,-3]]; + stroke(path, endcaps=dblarrow); +``` + +Trimmed: + +```openscad-2D + path = [[0,0], [-10,10], [0,20], [10,20], [10,10]]; + dblarrow = [[0,0], [2,-3], [0.5,-2.3], [2,-4], [0.5,-3.5], [-0.5,-3.5], [-2,-4], [-0.5,-2.3], [-2,-3]]; + stroke(path, trim=3.5, endcaps=dblarrow); +``` + +### Standard 2D Shape Polygons +BOSL2 will let you get the perimeter polygon for almost all of the standard 2D shapes simply by calling them like a function: + +```openscad-2D + path = square(40, center=true); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = rect([40,30], rounding=5, center=true); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = trapezoid(w1=40, w2=20, h=30); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = circle(d=50); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = oval(d=[50,30]); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = pentagon(d=50); + stroke(path, closed=true, endcap2="arrow2"); +``` + +```openscad-2D + path = star(n=5, step=2, d=50); + stroke(path, closed=true, endcap2="arrow2"); +``` + +### Arcs +Often, when you are constructing a path, you will want to add an arc. The `arc()` command lets you do that: + +```openscad-2D + path = arc(r=30, angle=120); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = arc(d=60, angle=120); + stroke(path, endcap2="arrow2"); +``` + +If you give the `N=` argument, you can control exactly how many points the arc is divided into: + +```openscad-2D + path = arc(N=5, r=30, angle=120); + stroke(path, endcap2="arrow2"); +``` + +With the `start=` argument, you can start the arc somewhere other than the X+ axis: + +```openscad-2D + path = arc(start=45, r=30, angle=120); + stroke(path, endcap2="arrow2"); +``` + +Alternatively, you can give starting and ending angles in a list in the `angle=` argument: + +```openscad-2D + path = arc(angle=[120,45], r=30); + stroke(path, endcap2="arrow2"); +``` + +The `cp=` argument lets you center the arc somewhere other than the origin: + +```openscad-2D + path = arc(cp=[10,0], r=30, angle=120); + stroke(path, endcap2="arrow2"); +``` + +The arc can also be given by three points on the arc: + +```openscad-2D + pts = [[-15,10],[0,20],[35,-5]]; + path = arc(points=pts); + stroke(path, endcap2="arrow2"); +``` + + +### Turtle Graphics +Another way you can create a path is using the `turtle()` command. It implements a simple path +description language that is similar to LOGO Turtle Graphics. The concept is that you have a virtial +turtle or cursor walking a path. It can "move" forward or backward, or turn "left" or "right" in +place: + +```openscad-2D + path = turtle([ + "move", 10, + "left", 90, + "move", 20, + "left", 135, + "move", 10*sqrt(2), + "right", 90, + "move", 10*sqrt(2), + "left", 135, + "move", 20 + ]); + stroke(path, endcap2="arrow2"); +``` + +The position and the facing of the turtle/cursor updates after each command. The motion and turning +commands can also have default distances or angles given: + +```openscad-2D + path = turtle([ + "angle",360/6, + "length",10, + "move","turn", + "move","turn", + "move","turn", + "move","turn", + "move" + ]); + stroke(path, endcap2="arrow2"); +``` + +You can use "scale" to relatively scale up the default motion length: + +```openscad-2D + path = turtle([ + "angle",360/6, + "length",10, + "move","turn", + "move","turn", + "scale",2, + "move","turn", + "move","turn", + "scale",0.5, + "move" + ]); + stroke(path, endcap2="arrow2"); +``` + +Sequences of commands can be repeated using the "repeat" command: + +```openscad-2D + path=turtle([ + "angle",360/5, + "length",10, + "repeat",5,["move","turn"] + ]); + stroke(path, endcap2="arrow2"); +``` + +More complicated commands also exist, including those that form arcs: + +```openscad-2D + path = turtle([ + "move", 10, + "left", 90, + "move", 20, + "arcleft", 10, 180, + "move", 20 + ]); + stroke(path, endcap2="arrow2"); +``` + +A comprehensive list of supported turtle commands can be found in the docs for [`turtle()`](shapes2d.scad#turtle). + +### Transforming Paths and Polygons +To translate a path, you can just pass it to the `move()` (or up/down/left/right/fwd/back) function in the `p=` argument: + +```openscad-2D + path = move([-15,-30], p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = fwd(30, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = left(30, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +To scale a path, you can just pass it to the `scale()` (or [xyz]scale) function in the `p=` argument: + +```openscad-2D + path = scale([1.5,0.75], p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = xscale(1.5, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = yscale(1.5, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +To rotate a path, just can pass it to the `rot()` (or [xyz]rot) function in the `p=` argument: + +```openscad-2D + path = rot(30, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = zrot(30, p=square(50,center=true)); + stroke(path, endcap2="arrow2"); +``` + +To mirror a path, just can pass it to the `mirror()` (or [xyz]flip) function in the `p=` argument: + +```openscad-2D + path = mirror([1,1], p=trapezoid(w1=10, w2=0, h=5)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = xflip(p=trapezoid(w1=10, w2=0, h=5)); + stroke(path, endcap2="arrow2"); +``` + +```openscad-2D + path = yflip(p=trapezoid(w1=10, w2=0, h=5)); + stroke(path, endcap2="arrow2"); +``` + +You can get raw transformation matrices for various transformations by calling them like a function without a `p=` argument: + +```openscad-2D + mat = move([5,10]); + multmatrix(mat) square(50,center=true); +``` + +```openscad-2D + mat = scale([1.5,0.75]); + multmatrix(mat) square(50,center=true); +``` + +```openscad-2D + mat = rot(30); + multmatrix(mat) square(50,center=true); +``` + +Raw transformation matrices can be multiplied together to precalculate a compound transformation. For example, to scale a shape, then rotate it, then translate the result, you can do something like: + +```openscad-2D + mat = move([5,10]) * rot(30, planar=true) * scale([1.5,0.75]); + multmatrix(mat) square(50,center=true); +``` + +To apply a compound transformation matrix to a path, you can use the `apply()` function: + +```openscad-2D + mat = move([5,10]) * rot(30, planar=true) * scale([1.5,0.75]); + path = square(50,center=true); + tpath = apply(mat, path); + stroke(tpath, endcap2="arrow2"); +``` + + +### Regions +A polygon is good to denote a single closed 2D shape with no holes in it. For more complex 2D +shapes, you will need to use regions. A region is a list of 2D polygons, where each polygon is +XORed against all the others. You can display a region using the `region()` module. + +If you have a region with one polygon fully inside another, it makes a hole: + +```openscad-2D + rgn = [square(50,center=true), circle(d=30)]; + region(rgn); +``` + +If you have a region with multiple polygons that are not contained by any others, they make multiple discontiguous shapes: + +```openscad-2D + rgn = [ + move([-30, 20], p=square(20,center=true)), + move([ 0,-20], p=trapezoid(w1=20, w2=10, h=20)), + move([ 30, 20], p=square(20,center=true)), + ]; + region(rgn); +``` + +Region polygons can be nested abitrarily deep, in multiple discontiguous shapes: + +```openscad-2D + rgn = [ + for (d=[50:-10:10]) left(30, p=circle(d=d)), + for (d=[50:-10:10]) right(30, p=circle(d=d)) + ]; + region(rgn); +``` + +A region with crossing polygons is somewhat poorly formed, but the intersection(s) of the polygons become holes: + +```openscad-2D + rgn = [ + left(15, p=circle(d=50)), + right(15, p=circle(d=50)) + ]; + region(rgn); +``` + +### Boolean Region Geometry +Similarly to how OpenSCAD can perform operations like union/difference/intersection/offset on shape geometry, +the BOSL2 library lets you perform those same operations on regions: + +```openscad-2D + rgn1 = [for (d=[40:-10:10]) circle(d=d)]; + rgn2 = [square([60,12], center=true)]; + rgn = union(rgn1, rgn2); + region(rgn); +``` + +```openscad-2D + rgn1 = [for (d=[40:-10:10]) circle(d=d)]; + rgn2 = [square([60,12], center=true)]; + rgn = difference(rgn1, rgn2); + region(rgn); +``` + +```openscad-2D + rgn1 = [for (d=[40:-10:10]) circle(d=d)]; + rgn2 = [square([60,12], center=true)]; + rgn = exclusive_or(rgn1, rgn2); + region(rgn); +``` + +```openscad-2D + rgn1 = [for (d=[40:-10:10]) circle(d=d)]; + rgn2 = [square([60,12], center=true)]; + rgn = intersection(rgn1, rgn2); + region(rgn); +``` + +```openscad-2D + orig_rgn = [star(n=5, step=2, d=50)]; + rgn = offset(orig_rgn, r=-3, closed=true); + color("blue") region(orig_rgn); + region(rgn); +``` + +You can use regions for several useful things. If you wanted a grid of holes in your object that +form the shape given by a region, you can do that with `grid2d()`: + +```openscad-3D + rgn = [ + circle(d=100), + star(n=5,step=2,d=100,spin=90) + ]; + difference() { + cyl(h=5, d=120); + grid2d(size=[120,120], spacing=[4,4], inside=rgn) cyl(h=10,d=2); + } +``` + +You can also sweep a region through 3-space to make a solid: + +```openscad-3D + $fa=1; $fs=1; + rgn = [ for (d=[50:-10:10]) circle(d=d) ]; + tforms = [ + for (a=[90:-5:0]) xrot(a, cp=[0,-70]), + for (a=[0:5:90]) xrot(a, cp=[0,70]), + move([0,150,-70]) * xrot(90), + ]; + sweep(rgn, tforms, closed=false, caps=true); +``` + + + diff --git a/tutorials/Shapes2d.md b/tutorials/Shapes2d.md new file mode 100644 index 0000000..28b353b --- /dev/null +++ b/tutorials/Shapes2d.md @@ -0,0 +1,553 @@ +# 2D Shapes Tutorial + +## Primitives +There are two built-in 2D primitive shapes that OpenSCAD provides: `square()`, and `circle()`. +The BOSL2 library provides alternative to these shapes so that they support more features, +and more ways to simply reorient them. + + +### 2D Squares +You can still use the built-in `square()` in the familiar ways that OpenSCAD provides: + +```openscad-2D + square(100, center=false); +``` + +```openscad-2D + square(100, center=true); +``` + +```openscad-2D + square([60,40], center=true); +``` + +The BOSL2 library provides an enhanced equivalent to `square()` called `rect()`. +You can use it in the same way you use `square()`, but it also provides +extended functionality. For example, it allows you to round the corners: + +```openscad-2D + rect([60,40], center=true, rounding=10); +``` + +Or chamfer them: + +```openscad-2D + rect([60,40], center=true, chamfer=10); +``` + +You can even specify *which* corners get rounded or chamfered. If you pass a +list of four size numbers to the `rounding=` or `chamfer=` arguments, it will +give each corner its own size. In order, it goes from the back-right (quadrant I) +corner, counter-clockwise around to the back-left (quadrant II) corner, to the +forward-left (quadrant III) corner, to the forward-right (quadrant IV) corner: + +```openscad-2DImgOnly + module text3d(text) color("black") text( + text=text, font="Times", size=10, + halign="center", valign="center" + ); + translate([ 50, 50]) text3d("I"); + translate([-50, 50]) text3d("II"); + translate([-50,-50]) text3d("III"); + translate([ 50,-50]) text3d("IV"); + rect([90,80], center=true); +``` + +If a size is given as `0`, then there is no rounding and/or chamfering for +that quadrant's corner: + +```openscad-2D + rect([60,40], center=true, rounding=[0,5,10,15]); +``` + +```openscad-2D + rect([60,40], center=true, chamfer=[0,5,10,15]); +``` + +You can give both `rounding=` and `chamfer=` arguments to mix rounding and +chamfering, but only if you specify per corner. If you want a rounding in +a corner, specify a 0 chamfer for that corner, and vice versa: + +```openscad-2D + rect([60,40], center=true, rounding=[5,0,10,0], chamfer=[0,5,0,15]); +``` + +#### Anchors and Spin +Another way that `rect()` is enhanced over `square()`, is that you can anchor, +spin and attach it. + +The `anchor=` argument is an alternative to `center=`, which allows more +alignment options. It takes a vector as a value, pointing roughly towards +the side or corner you want to align to the origin. For example, to align +the center of the back edge to the origin, set the anchor to `[0,1]`: + +```openscad-2D + rect([60,40], anchor=[0,1]); +``` + +To align the front right corner to the origin: + +```openscad-2D + rect([60,40], anchor=[1,-1]); +``` + +To center: + +```openscad-2D + rect([60,40], anchor=[0,0]); +``` + +To make it clearer when giving vectors, there are several standard vector +constants defined: + +Constant | Direction | Value +-------- | --------- | ----------- +`LEFT` | X- | `[-1, 0, 0]` +`RIGHT` | X+ | `[ 1, 0, 0]` +`FRONT`/`FORWARD`/`FWD` | Y- | `[ 0,-1, 0]` +`BACK` | Y+ | `[ 0, 1, 0]` +`BOTTOM`/`BOT`/`BTM`/`DOWN` | Z- | `[ 0, 0,-1]` (3D only.) +`TOP`/`UP` | Z+ | `[ 0, 0, 1]` (3D only.) +`CENTER`/`CTR` | Centered | `[ 0, 0, 0]` + +Note that even though these are 3D vectors, you can use most of them, +(except `UP`/`DOWN`, of course) for anchors in 2D shapes: + +```openscad-2D + rect([60,40], anchor=BACK); +``` + +```openscad-2D + rect([60,40], anchor=CENTER); +``` + +You can add vectors together to point to corners: + +```openscad-2D + rect([60,40], anchor=FRONT+RIGHT); +``` + +Finally, the `spin` argument can rotate the shape by a given number of degrees +clockwise: + +```openscad-2D + rect([60,40], anchor=CENTER, spin=30); +``` + +Anchoring or centering is performed before the spin: + +```openscad-2D + rect([60,40], anchor=BACK, spin=30); +``` + +Anchor points double as attachment points, so that you can attach other shapes: + +```openscad-2D + rect([60,40],center=true) + show_anchors(); +``` + +### 2D Circles and Ovals +The built-in `circle()` primitive can be used as expected: + +```openscad-2D + circle(r=50); +``` + +```openscad-2D + circle(d=100); +``` + +```openscad-2D + circle(d=100, $fn=8); +``` + +The BOSL2 library also provides an enhanced equivalent of `circle()` called `oval()`. +You can use it in the same way you use `circle()`, but it also provides extended +functionality. For example, it allows more control over its size and orientation. + +Since a circle in OpenSCAD can only be approximated by a regular polygon with +a number of straight sides, this can lead to size and shape inaccuracies. +To counter this, the `realign=` and `circum=` arguments are also provided. + +The `realign=` argument, if set `true`, rotates the `oval()` by half the angle +between the sides: + +```openscad-2D + oval(d=100, $fn=8, realign=true); +``` + +The `circum=` argument, if true, makes it so that the polygon forming the +`oval()` circumscribes the ideal circle instead of inscribing it. + +Inscribing the ideal circle: + +```openscad-2D + difference() { + circle(d=100, $fn=360); + oval(d=100, $fn=8); + } +``` + +Circumscribing the ideal circle: + +```openscad-2D + difference() { + oval(d=100, $fn=8, circum=true); + circle(d=100, $fn=360); + } +``` + +The `oval()` module, as its name suggests, can be given separate X and Y radii +or diameters. To do this, just give `r=` or `d=` with a list of two radii or +diameters: + +```openscad-2D + oval(r=[30,20]); +``` + +```openscad-2D + oval(d=[60,40]); +``` + +Another way that `oval()` is enhanced over `circle()`, is that you can anchor, +spin and attach it. + +```openscad-2D + oval(r=50, anchor=BACK); +``` + +```openscad-2D + oval(r=50, anchor=FRONT+RIGHT); +``` + +Using spin on a circle may not make initial sense, until you remember that +anchoring is performed before spin: + +```openscad-2D + oval(r=50, anchor=FRONT, spin=-30); +``` + + +### Trapezoids + +OpenSCAD doesn't provide a simple way to make 2D triangles, trapezoids, or parallelograms. +The BOSL2 library can provide all of these shapes with the `trapezoid()` module. + +To make a simple triangle, just make one of the widths zero: + +```openscad-2D + trapezoid(w1=50, w2=0, h=50); +``` + +To make a right triangle, you need to use the `shift=` argument, to shift the back of the trapezoid along the X axis: + +```openscad-2D + trapezoid(w1=50, w2=0, h=50, shift=-25); +``` + +```openscad-2D + trapezoid(w1=50, w2=0, h=50, shift=25); +``` + +```openscad-2D + trapezoid(w1=0, w2=50, h=50, shift=-25); +``` + +```openscad-2D + trapezoid(w1=0, w2=50, h=50, shift=25); +``` + +You can make a trapezoid by specifying non-zero widths for both the front (`w1=`) and back (`w2=`): + +```openscad-2D + trapezoid(w1=30, w2=50, h=50); +``` + +A parallelogram is just a matter of using the same width for front and back, with a shift along the X axis: + +```openscad-2D + trapezoid(w1=50, w2=50, shift=20, h=50); +``` + +A quadrilateral can be made by having unequal, non-zero front (`w1=`) and back (`w2=`) widths, with the back shifted along the X axis: + +```openscad-2D + trapezoid(w1=50, w2=30, shift=20, h=50); +``` + +You can use `anchor=` and `spin=`, just like with other attachable shapes. However, the anchor +points are based on the side angles of the faces, and may not be where you expect them: + +```openscad-2D + trapezoid(w1=30, w2=50, h=50) + show_anchors(); +``` + +### Regular N-Gons + +OpenSCAD lets you make regular N-gons (pentagon, hexagon, etc) by using `circle()` with `$fn`. +While this is concise, it may be less than obvious at first glance: + +```openscad-2D + circle(d=50, $fn=5); +``` + +The BOSL2 library has modules that are named more clearly: + +```openscad-2D + pentagon(d=50); +``` + +```openscad-2D + hexagon(d=50); +``` + +```openscad-2D + octagon(d=50); +``` + +```openscad-2D + regular_ngon(n=7, d=50); +``` + +These modules also provide you with extra functionality. + +They can be sized by side length: + +```openscad-2D + pentagon(side=20); +``` + +They can be sized by circumscribed circle radius/diameter: + +```openscad-2D + pentagon(ir=25); + pentagon(id=50); +``` + +They can be realigned by half a side's angle: + +```openscad-2D + left(30) pentagon(d=50, realign=true); + right(30) pentagon(d=50, realign=false); +``` + +They can be rounded: + +```openscad-2D + pentagon(d=50, rounding=10); +``` + +```openscad-2D + hexagon(d=50, rounding=10); +``` + +They also have somewhat different attachment behavior: + +```openscad-2D + color("green") stroke(circle(d=50), closed=true); + oval(d=50,$fn=5) + attach(LEFT) color("blue") anchor_arrow2d(); +``` + +```openscad-2D + pentagon(d=50) + attach(LEFT) color("blue") anchor_arrow2d(); +``` + +You can use `anchor=` and `spin=`, just like with other attachable shapes. However, the anchor +points are based on where the anchor vector would intersect the side of the N-gon, and may not +be where you expect them: + +```openscad-2D + pentagon(d=50) + show_anchors(custom=false); +``` + +N-gons also have named anchor points for their sides and tips: + +```openscad-2D + pentagon(d=30) + show_anchors(std=false); +``` + + +### Stars + +The BOSL2 library has stars as a basic supported shape. They can have any number of points. +You can specify a star's shape by point count, inner and outer vertex radius/diameters: + +```openscad-2D + star(n=3, id=10, d=50); +``` + +```openscad-2D + star(n=5, id=15, r=25); +``` + +```openscad-2D + star(n=10, id=30, d=50); +``` + +Or you can specify the star shape by point count and number of points to step: + +```openscad-2D + star(n=7, step=2, d=50); +``` + +```openscad-2D + star(n=7, step=3, d=50); +``` + +If the `realign=` argument is given a true value, then the star will be rotated by half a point angle: + +```openscad-2D + left(30) star(n=5, step=2, d=50); + right(30) star(n=5, step=2, d=50, realign=true); +``` + +The `align_tip=` argument can be given a vector so that you can align the first point in a specific direction: + +```openscad-2D + star(n=5, ir=15, or=30, align_tip=BACK+LEFT) + attach("tip0") color("blue") anchor_arrow2d(); +``` + +```openscad-2D + star(n=5, ir=15, or=30, align_tip=BACK+RIGHT) + attach("tip0") color("blue") anchor_arrow2d(); +``` + +Similarly, the first indentation or pit can be oriented towards a specific vector with `align_pit=`: + + +```openscad-2D + star(n=5, ir=15, or=30, align_pit=BACK+LEFT) + attach("pit0") color("blue") anchor_arrow2d(); +``` + +```openscad-2D + star(n=5, ir=15, or=30, align_pit=BACK+RIGHT) + attach("pit0") color("blue") anchor_arrow2d(); +``` + +You can use `anchor=` and `spin=`, just like with other attachable shapes. However, the anchor +points are based on the furthest extents of the shape, and may not be where you expect them: + +```openscad-2D + star(n=5, step=2, d=50) + show_anchors(custom=false); +``` + +Stars also have named anchor points for their pits, tips, and midpoints between tips: + +```openscad-2D + star(n=5, step=2, d=40) + show_anchors(std=false); +``` + + + +### Teardrop2D + +Often when 3D printing, you may want to make a circular hole in a vertical wall. If the hole is +too big, however, the overhang at the top of the hole can cause problems with printing on an +FDM/FFF printer. If you don't want to use support material, you can just use the teardrop shape. +The `teardrop2d()` module will let you make a 2D version of the teardrop shape, so that you can +extrude it later: + +```openscad-2D + teardrop2d(r=20); +``` + +```openscad-2D + teardrop2d(d=50); +``` + +The default overhang angle is 45 degrees, but you can adjust that with the `ang=` argument: + +```openscad-2D + teardrop2d(d=50, ang=30); +``` + +If you prefer to flatten the top of the teardrop, to encourage bridging, you can use the `cap_h=` +argument: + +```openscad-2D + teardrop2d(d=50, cap_h=25); +``` + +```openscad-2D + teardrop2d(d=50, ang=30, cap_h=30); +``` + +You can use `anchor=` and `spin=`, just like with other attachable shapes. However, the anchor +points are based on the furthest extents of the shape, and may not be where you expect them: + +```openscad-2D + teardrop2d(d=50, ang=30, cap_h=30) + show_anchors(); +``` + + +### Glued Circles + +A more unusal shape that BOSL2 provides is Glued Circles. It's basically a pair of circles, +connected by what looks like a gloopy glued miniscus: + +```openscad-2D + glued_circles(d=30, spread=40); +``` + +The `r=`/`d=` arguments can specify the radius or diameter of the two circles: + +```openscad-2D + glued_circles(r=20, spread=45); +``` + +```openscad-2D + glued_circles(d=40, spread=45); +``` + +The `spread=` argument specifies the distance between the centers of the two circles: + +```openscad-2D + glued_circles(d=30, spread=30); +``` + +```openscad-2D + glued_circles(d=30, spread=40); +``` + +The `tangent=` argument gives the angle of the tangent of the meniscus on the two circles: + +```openscad-2D + glued_circles(d=30, spread=30, tangent=45); +``` + +```openscad-2D + glued_circles(d=30, spread=30, tangent=20); +``` + +```openscad-2D + glued_circles(d=30, spread=30, tangent=-20); +``` + +One useful thing you can do is to string a few `glued_circle()`s in a line then extrude them to make a ribbed wall: + +```openscad-3D + $fn=36; s=10; + linear_extrude(height=50,convexity=16,center=true) + xcopies(s*sqrt(2),n=3) + glued_circles(d=s, spread=s*sqrt(2), tangent=45); +``` + +You can use `anchor=` and `spin=`, just like with other attachable shapes. However, the anchor +points are based on the furthest extents of the shape, and may not be where you expect them: + +```openscad-2D + glued_circles(d=40, spread=40, tangent=45) + show_anchors(); +``` + diff --git a/tutorials/Basic_Shapes.md b/tutorials/Shapes3d.md similarity index 55% rename from tutorials/Basic_Shapes.md rename to tutorials/Shapes3d.md index 9f848b5..c65f2c0 100644 --- a/tutorials/Basic_Shapes.md +++ b/tutorials/Shapes3d.md @@ -1,233 +1,13 @@ # Basic Shapes Tutorial ## Primitives -There are 5 built-in primitive shapes that OpenSCAD provides. -`square()`, `circle()`, `cube()`, `cylinder()`, and `sphere()`. -The BOSL2 library extends or provides alternative to these shapes so +There are 3 built-in 3D primitive shapes that OpenSCAD provides: `cube()`, `cylinder()`, +and `sphere()`. The BOSL2 library extends and provides alternative to these shapes so that they support more features, and more ways to simply reorient them. -### 2D Squares -You can still use the built-in `square()` in the familiar ways that OpenSCAD provides: - -```openscad-2D - square(100, center=false); -``` - -```openscad-2D - square(100, center=true); -``` - -```openscad-2D - square([60,40], center=true); -``` - -The BOSL2 library provides an enhanced equivalent to `square()` called `rect()`. -You can use it in the same way you use `square()`, but it also provides -extended functionality. For example, it allows you to round the corners: - -```openscad-2D - rect([60,40], center=true, rounding=10); -``` - -Or chamfer them: - -```openscad-2D - rect([60,40], center=true, chamfer=10); -``` - -You can even specify *which* corners get rounded or chamfered. If you pass a -list of four size numbers to the `rounding=` or `chamfer=` arguments, it will -give each corner its own size. In order, it goes from the back-right (quadrant I) -corner, counter-clockwise around to the back-left (quadrant II) corner, to the -forward-left (quadrant III) corner, to the forward-right (quadrant IV) corner: - -```openscad-2DImgOnly - module text3d(text) color("black") text( - text=text, font="Times", size=10, - halign="center", valign="center" - ); - translate([ 50, 50]) text3d("I"); - translate([-50, 50]) text3d("II"); - translate([-50,-50]) text3d("III"); - translate([ 50,-50]) text3d("IV"); - rect([90,80], center=true); -``` - -If a size is given as `0`, then there is no rounding and/or chamfering for -that quadrant's corner: - -```openscad-2D - rect([60,40], center=true, rounding=[0,5,10,15]); -``` - -```openscad-2D - rect([60,40], center=true, chamfer=[0,5,10,15]); -``` - -You can give both `rounding=` and `chamfer=` arguments to mix rounding and -chamfering, but only if you specify per corner. If you want a rounding in -a corner, specify a 0 chamfer for that corner, and vice versa: - -```openscad-2D - rect([60,40], center=true, rounding=[5,0,10,0], chamfer=[0,5,0,15]); -``` - -#### Anchors and Spin -Another way that `rect()` is enhanced over `square()`, is that you can anchor, -spin and attach it. - -The `anchor=` argument is an alternative to `center=`, which allows more -alignment options. It takes a vector as a value, pointing roughly towards -the side or corner you want to align to the origin. For example, to align -the center of the back edge to the origin, set the anchor to `[0,1]`: - -```openscad-2D - rect([60,40], anchor=[0,1]); -``` - -To align the front right corner to the origin: - -```openscad-2D - rect([60,40], anchor=[1,-1]); -``` - -To center: - -```openscad-2D - rect([60,40], anchor=[0,0]); -``` - -To make it clearer when giving vectors, there are several standard vector -constants defined: - -Constant | Direction | Value --------- | --------- | ----------- -`LEFT` | X- | `[-1, 0, 0]` -`RIGHT` | X+ | `[ 1, 0, 0]` -`FRONT`/`FORWARD`/`FWD` | Y- | `[ 0,-1, 0]` -`BACK` | Y+ | `[ 0, 1, 0]` -`BOTTOM`/`BOT`/`BTM`/`DOWN` | Z- | `[ 0, 0,-1]` (3D only.) -`TOP`/`UP` | Z+ | `[ 0, 0, 1]` (3D only.) -`CENTER`/`CTR` | Centered | `[ 0, 0, 0]` - -Note that even though these are 3D vectors, you can use most of them, -(except `UP`/`DOWN`, of course) for anchors in 2D shapes: - -```openscad-2D - rect([60,40], anchor=BACK); -``` - -```openscad-2D - rect([60,40], anchor=CENTER); -``` - -You can add vectors together to point to corners: - -```openscad-2D - rect([60,40], anchor=FRONT+RIGHT); -``` - -Finally, the `spin` argument can rotate the shape by a given number of degrees -clockwise: - -```openscad-2D - rect([60,40], anchor=CENTER, spin=30); -``` - -Anchoring or centering is performed before the spin: - -```openscad-2D - rect([60,40], anchor=BACK, spin=30); -``` - - -### 2D Circles -The built-in `circle()` primitive can be used as expected: - -```openscad-2D - circle(r=50); -``` - -```openscad-2D - circle(d=100); -``` - -```openscad-2D - circle(d=100, $fn=8); -``` - -The BOSL2 library provides an enhanced equivalent of `circle()` called `oval()`. -You can use it in the same way you use `circle()`, but it also provides -extended functionality. For example, it allows more control over its size and -orientation. - -Since a circle in OpenSCAD can only be approximated by a regular polygon with -a number of straight sides, this can lead to size and shape inaccuracies. -To counter this, the `realign=` and `circum=` arguments are also provided. - -The `realign=` argument, if set `true`, rotates the `oval()` by half the angle -between the sides: - -```openscad-2D - oval(d=100, $fn=8, realign=true); -``` - -The `circum=` argument, if true, makes it so that the polygon forming the -`oval()` circumscribes the ideal circle instead of inscribing it. - -Inscribing the ideal circle: - -```openscad-2D - difference() { - circle(d=100, $fn=360); - oval(d=100, $fn=8); - } -``` - -Circumscribing the ideal circle: - -```openscad-2D - difference() { - oval(d=100, $fn=8, circum=true); - circle(d=100, $fn=360); - } -``` - -The `oval()` module, as its name suggests, can be given separate X and Y radii -or diameters. To do this, just give `r=` or `d=` with a list of two radii or -diameters: - -```openscad-2D - oval(r=[30,20]); -``` - -```openscad-2D - oval(d=[60,40]); -``` - -Another way that `oval()` is enhanced over `circle()`, is that you can anchor, -spin and attach it. - -```openscad-2D - oval(r=50, anchor=BACK); -``` - -```openscad-2D - oval(r=50, anchor=FRONT+RIGHT); -``` - -Using spin on a circle may not make initial sense, until you remember that -anchoring is performed before spin: - -```openscad-2D - oval(r=50, anchor=FRONT, spin=-30); -``` - - ### 3D Cubes -BOSL2 overrides the built-in `cube()` module. It still can be used as you -expect from the built-in: +BOSL2 overrides the built-in `cube()` module. It still can be used as you expect from the built-in: ```openscad-3D cube(100); @@ -243,7 +23,7 @@ expect from the built-in: It is also enhanced to allow you to anchor, spin, orient, and attach it. -You can use `anchor=` similarly to how you use it with `square()` or `rect()`, +You can use `anchor=` similarly to how you use it with `rect()` or `oval()`, except you can also anchor vertically in 3D, allowing anchoring to faces, edges, and corners: @@ -546,11 +326,20 @@ The "stagger" style will stagger the triangulation of the vertical rows: spheroid(d=100, style="stagger", $fn=20); ``` -The "icosa"` style will make for roughly equal-sized triangles for the entire -sphere surface: +The "icosa" style will make for roughly equal-sized triangles for the entire +sphere surface, based on subdividing an icosahedron. This style will round the +effective `$fn` to a multiple of 5 when constructing the spheroid: ```openscad-3D spheroid(d=100, style="icosa", $fn=20); ``` +The "octa" style will also make for roughly equal-sized triangles for the entire +sphere surface, but based on subdividing an octahedron. This is useful in that it +guarantees vertices at the axis extrema. This style will round the effective `$fn` +to a multiple of 4 when constructing the spheroid: + +```openscad-3D + spheroid(d=100, style="octa", $fn=20); +``` diff --git a/version.scad b/version.scad index 15bdab9..b9ab152 100644 --- a/version.scad +++ b/version.scad @@ -8,7 +8,7 @@ ////////////////////////////////////////////////////////////////////// -BOSL_VERSION = [2,0,486]; +BOSL_VERSION = [2,0,487]; // Section: BOSL Library Version Functions