Minor tweaks to Shapes2d tutorital.

screw_drive.scad

@@ -16,7 +16,7 @@
 //   Creates a mask for creating a Phillips drive recess given the Phillips size.  Each mask can
 //   be lowered to different depths to create different sizes of recess.  
 // Arguments:
-//   size = The size of the bit as a number or string.  "#0", "#1", "#2", "#3", or "#4"
+//   size = The size of the bit as an integer or string.  "#0", "#1", "#2", "#3", or "#4"
 //   ---
 //   anchor = Translate so anchor point is at origin (0,0,0).  See [anchor](attachments.scad#subsection-anchor).  Default: `CENTER`
 //   spin = Rotate this many degrees around the Z axis after anchor.  See [spin](attachments.scad#subsection-spin).  Default: `0`
@@ -323,4 +323,46 @@ module torx_mask(size, l=5, center, anchor, spin=0, orient=UP) {
 }
 
 
+// Section: Robertson/Square Drives
+
+// Module: robertson_mask()
+// Usage:
+//   robertson_mask(size, [extra]);
+// Description:
+//   Creates a mask for creating a Robertson/Square drive recess given the drive size as an integer.
+// Arguments:
+//   size = The size of the square drive, as an integer from 0 to 4.
+//   extra = Extra length of drive mask to create.
+// Example:
+//   robertson_mask(size=2);
+// Example:
+//   difference() {
+//       cyl(d1=2, d2=8, h=4, anchor=TOP);
+//       robertson_mask(size=2);
+//   }
+module robertson_mask(size, extra=1) {
+    assert(is_int(size) && size>=0 && size<=4);
+    Mmin = [0.0696, 0.0900, 0.1110, 0.1315, 0.1895][size];
+    Mmax = [0.0710, 0.0910, 0.1126, 0.1330, 0.1910][size];
+    M = (Mmin + Mmax) / 2 * INCH;
+    Tmin = [0.063, 0.105, 0.119, 0.155, 0.191][size];
+    Tmax = [0.073, 0.113, 0.140, 0.165, 0.201][size];
+    T = (Tmin + Tmax) / 2 * INCH;
+    Fmin = [0.032, 0.057, 0.065, 0.085, 0.090][size];
+    Fmax = [0.038, 0.065, 0.075, 0.095, 0.100][size];
+    F = (Fmin + Fmax) / 2 * INCH;
+    ang = 2;
+    h = T + extra;
+    down(T) {
+        intersection(){
+            Mtop = M + 2*adj_ang_to_opp(F+extra,ang);
+            Mbot = M - 2*adj_ang_to_opp(T-F,ang);
+            prismoid([Mbot,Mbot],[Mtop,Mtop],h=h,anchor=BOT);
+            cyl(d1=0, d2=M/(T-F)*sqrt(2)*h, h=h, anchor=BOT);
+        }
+    }
+}
+
+
+
 // vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap

shapes2d.scad

@@ -729,11 +729,11 @@ module octagon(r, d, or, od, ir, id, side, rounding=0, realign=false, align_tip,
 //   ---
 //   anchor = Translate so anchor point is at origin (0,0,0).  See [anchor](attachments.scad#subsection-anchor).  Default: `CENTER`
 //   spin = Rotate this many degrees around the Z axis after anchor.  See [spin](attachments.scad#subsection-spin).  Default: `0`
-// Example:
+// Example(2D):
 //   right_triangle([40,30]);
-// Example: With `center=true`
+// Example(2D): With `center=true`
 //   right_triangle([40,30], center=true);
-// Example: Anchors
+// Example(2D): Anchors
 //   right_triangle([40,30])
 //       show_anchors();
 function right_triangle(size=[1,1], center, anchor, spin=0) =

tutorials/Shapes2d.md

@@ -133,7 +133,7 @@ square(50, center=true)
 
 ```openscad-2D
 square(50, center=true)
-    #square([30,50], anchor=FWD);
+    #square([20,40], anchor=FWD);
 ```
 
 By adding the `position()` module, you can position the child at any anchorpoint on the parent:
@@ -177,25 +177,25 @@ module.  It does not position the child.  It only rotates it:
 ```openscad-2D
 square(50, center=true)
     orient(anchor=LEFT)
-        #square([10,50], anchor=FWD);
+        #square([10,40], anchor=FWD);
 ```
 
 ```openscad-2D
 square(50, center=true)
     orient(anchor=FWD)
-        #square([10,50], anchor=FWD);
+        #square([10,40], anchor=FWD);
 ```
 
 ```openscad-2D
 square(50, center=true)
     orient(anchor=RIGHT)
-        #square([10,50], anchor=FWD);
+        #square([10,40], anchor=FWD);
 ```
 
 ```openscad-2D
 circle(d=50)
     orient(polar_to_xy(1,30))
-        #square([10,50], anchor=FWD);
+        #square([10,40], anchor=FWD);
 ```
 
 You can use `position()` and `orient()` together to both position and orient to an anchorpoint:
@@ -204,7 +204,7 @@ You can use `position()` and `orient()` together to both position and orient to
 square(50, center=true)
     position(RIGHT+BACK)
         orient(anchor=RIGHT+BACK)
-            #square([10,50], anchor=FWD);
+            #square([10,40], anchor=FWD);
 ```
 
 ```openscad-2D
@@ -219,13 +219,13 @@ But it's simpler to just use the `attach()` module to do both at once:
 ```openscad-2D
 square(50, center=true)
     attach(LEFT+BACK)
-        #square([10,50], anchor=FWD);
+        #square([10,40], anchor=FWD);
 ```
 
 ```openscad-2D
 circle(d=50)
     attach(polar_to_xy(1,30))
-        #square([10,50], center=true);
+        #square([10,40], center=true);
 ```
 
 Instead of specifying the `anchor=` in the child, you can pass a second argument to `attach()`
@@ -234,18 +234,18 @@ that tells it which side of the child to attach to the parent:
 ```openscad-2D
 square([10,50], center=true)
     attach(BACK, LEFT)
-        #square([10,50], center=true);
+        #square([10,40], center=true);
 ```
 
 ```openscad-2D
 circle(d=50)
     attach(polar_to_xy(1,30), LEFT)
-        #square([10,50], center=true);
+        #square([10,40], center=true);
 ```
 
 
 
-#### `rect()`
+#### Rectangles
 
 The BOSL2 library provides an alternative to `square()`, that support more features.  It is
 called `rect()`.  You can use it in the same way you use `square()`, but it also provides
@@ -298,7 +298,7 @@ a corner, specify a 0 chamfer for that corner, and vice versa:
 rect([60,40], rounding=[5,0,10,0], chamfer=[0,5,0,15]);
 ```
 
-### `ellipse()`
+#### Ellipses
 
 The BOSL2 library also provides an enhanced equivalent of `circle()` called `ellipse()`.
 You can use it in the same way you use `circle()`, but it also provides extended
@@ -362,9 +362,47 @@ ellipse(d=50)
 ```
 
 
-### Trapezoids
+#### Right Triangles
+The BOSL2 library provides a simple way to make a 2D right triangle by using the `right_triangle()` module:
 
-OpenSCAD doesn't provide a simple way to make 2D triangles, trapezoids, or parallelograms.
+```openscad-2D
+right_triangle([40,30]);
+```
+
+You can use `xflip()` and `yflip()` to change which quadrant the triangle is formed in:
+
+```openscad-2D
+xflip() right_triangle([40,30]);
+```
+
+```openscad-2D
+yflip() right_triangle([40,30]);
+```
+
+```openscad-2D
+xflip() yflip() right_triangle([40,30]);
+```
+
+Or, alternatively, just rotate it into the correct quadrant with `spin=`:
+
+```openscad-2D
+right_triangle([40,30], spin=90);
+```
+
+```openscad-2D
+right_triangle([40,30], spin=-90);
+```
+
+You can also use anchoring with right triangles:
+
+```openscad-2D
+right_triangle([40,30], anchor=FWD+RIGHT);
+```
+
+
+#### Trapezoids
+
+OpenSCAD doesn't provide a simple way to make general 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:
@@ -417,7 +455,7 @@ trapezoid(w1=30, w2=50, h=50)
     show_anchors();
 ```
 
-### Regular N-Gons
+#### 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:
@@ -507,7 +545,7 @@ pentagon(d=30)
 ```
 
 
-### Stars
+#### 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:
@@ -583,7 +621,7 @@ star(n=5, step=2, d=40)
 
 
 
-### Teardrop2D
+#### 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
@@ -625,7 +663,7 @@ teardrop2d(d=50, ang=30, cap_h=30)
 ```
 
 
-### Glued Circles
+#### 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: