Add end anchors to path_sweep

attachments.scad

@@ -2774,6 +2774,41 @@ function reorient(
 function named_anchor(name, pos, orient=UP, spin=0) = [name, pos, orient, spin];
 
 
+function _force_rot(T) =
+   [for(i=[0:3])
+       [for(j=[0:3]) j<3 ? T[i][j] :
+                     i==3 ? 1
+                       : 0]];
+
+// Function: transform_anchor()
+// Synopsis: Creates an anchor data structure from a transformation matrix
+// Topics: Attachments
+// See Also: reorient(), attachable()
+// Usage:
+//   a = transform_anchor(name, transform, [flip]);
+// Description:
+//   Creates an anchor data structure from a transformation matrix.  For a step-by-step explanation of attachments,
+//   see the [Attachments Tutorial](Tutorial-Attachments).
+// Arguments:
+//   name = The string name of the anchor.  Lowercase.  Words separated by single dashes.  No spaces.
+//   transform = A rotation matrix (which may include translation)
+//   flip = If true, flip the anchor the opposite direction.  Default: false
+
+function transform_anchor(name, transform, flip=false) =
+  let(
+       pos = apply(transform,CTR),
+       rotpart = _force_rot(transform), 
+       dir = flip ? apply(rotpart,DOWN)
+                    : apply(rotpart,UP),
+       transform = flip? affine3d_rot_by_axis(apply(rotpart,BACK),180)*transform
+                         : transform,
+       decode=rot_decode(rot(to=UP,from=dir)*_force_rot(transform)),
+       spin = decode[0]*sign(decode[1].z)
+  )
+  [name, pos,dir,spin];
+
+
+
 // Function: attach_geom()
 // Synopsis: Returns the internal geometry description of an attachable object.
 // Topics: Attachments
@@ -3201,7 +3236,6 @@ function _attach_transform(anchor, spin, orient, geom, p) =
     assert(is_undef(orient) || is_vector(orient,3), str("Got: ",orient))
     let(
         anchor = default(anchor, CENTER),
-        
         spin   = default(spin,   0),
         orient = default(orient, UP),
         two_d = _attach_geom_2d(geom),
@@ -3209,12 +3243,13 @@ function _attach_transform(anchor, spin, orient, geom, p) =
             let(
                 anch = _find_anchor($attach_to, geom),
                 pos = anch[1]
-            ) two_d? (
+            )
-                assert(two_d && is_num(spin))
+            two_d?
-                affine3d_zrot(spin) *
+                assert(is_num(spin))
-                rot(to=FWD, from=point3d(anch[2])) *
+                affine3d_zrot(spin) 
-                affine3d_translate(point3d(-pos))
+                   * rot(to=FWD, from=point3d(anch[2])) 
-            ) : (
+                   * affine3d_translate(point3d(-pos))
+            :
                 assert(is_num(spin) || is_vector(spin,3))
                 let(
                     ang = vector_angle(anch[2], DOWN),
@@ -3222,40 +3257,33 @@ function _attach_transform(anchor, spin, orient, geom, p) =
                     ang2 = (anch[2]==UP || anch[2]==DOWN)? 0 : 180-anch[3],
                     axis2 = rot(p=axis,[0,0,ang2])
                 )
-                affine3d_rot_by_axis(axis2,ang) * (
+                affine3d_rot_by_axis(axis2,ang)
-                    is_num(spin)? affine3d_zrot(ang2+spin) : (
+                   * (is_num(spin)? affine3d_zrot(ang2+spin)
-                        affine3d_zrot(spin.z) *
+                                  : affine3d_zrot(spin.z) * affine3d_yrot(spin.y) * affine3d_xrot(spin.x) 
-                        affine3d_yrot(spin.y) *
+                                     * affine3d_zrot(ang2))
-                        affine3d_xrot(spin.x) *
+                   * affine3d_translate(point3d(-pos))
-                        affine3d_zrot(ang2)
-                    )
-                ) * affine3d_translate(point3d(-pos))
-            )
         ) : (
             let(
                 pos = _find_anchor(anchor, geom)[1]
-            ) two_d? (
+            )
-                assert(two_d && is_num(spin))
+            two_d? 
-                affine3d_zrot(spin) *
+                assert(is_num(spin))
-                affine3d_translate(point3d(-pos))
+                affine3d_zrot(spin) * affine3d_translate(point3d(-pos))
-            ) : (
+            :
                 assert(is_num(spin) || is_vector(spin,3))
                 let(
                     axis = vector_axis(UP,orient),
                     ang = vector_angle(UP,orient)
                 )
-                affine3d_rot_by_axis(axis,ang) * (
+                affine3d_rot_by_axis(axis,ang) 
-                    is_num(spin)? affine3d_zrot(spin) : (
+                    * ( is_num(spin)? affine3d_zrot(spin)  
-                        affine3d_zrot(spin.z) *
+                                    : affine3d_zrot(spin.z) * affine3d_yrot(spin.y) * affine3d_xrot(spin.x))
-                        affine3d_yrot(spin.y) *
+                    * affine3d_translate(point3d(-pos))
-                        affine3d_xrot(spin.x)
-                    )
-                ) * affine3d_translate(point3d(-pos))
-            )
         )
-    ) is_undef(p)? m :
+    )
-    is_vnf(p)? [(p==EMPTY_VNF? p : apply(m, p[0])), p[1]] :
+    is_undef(p)? m
-    apply(m, p);
+  : is_vnf(p) && p==EMPTY_VNF? p 
+  : apply(m, p);
 
 
 function _get_cp(geom) =

skin.scad

@@ -1481,6 +1481,11 @@ module spiral_sweep(poly, h, r, turns=1, taper, r1, r2, d, d1, d2, internal=fals
 // Anchor Types:
 //   "hull" = Anchors to the virtual convex hull of the shape.
 //   "intersect" = Anchors to the surface of the shape.
+// Extra Anchors:
+//   start = When `closed==false`, the origin point of the shape, on the starting face of the object
+//   end = When `closed==false`, the origin point of the shape, on the ending face of the object
+//   start-centroid = When `closed==false`, the centroid of the shape, on the starting face of the object
+//   end-centroid = When `closed==false`, the centroid of the shape, on the ending face of the object
 // Example(NoScales): A simple sweep of a square along a sine wave:
 //   path = [for(theta=[-180:5:180]) [theta/10, 10*sin(theta)]];
 //   sq = square(6,center=true);
@@ -1755,29 +1760,60 @@ module spiral_sweep(poly, h, r, turns=1, taper, r1, r2, d, d1, d2, internal=fals
 //     path_sweep(left(.05,square([1.1,1])), curve, closed=true,
 //                method="manual", normal=UP);
 //   }
+// Example(Med,NoScales,VPR=[78.1,0,43.2],VPT=[2.18042,-0.485127,1.90371],VPD=74.4017): The "start" and "end" anchors are located at the origin point of the swept shape.
+//   shape = back_half(right_half(star(n=5,id=5,od=10)),y=-1);
+//   path = arc(angle=[0,180],d=30);
+//   path_sweep(shape,path,method="natural"){
+//     attach(["start","end"]) anchor_arrow(s=5);
+//   }
+// Example(Med,NoScales,VPR=[78.1,0,43.2],VPT=[2.18042,-0.485127,1.90371],VPD=74.4017): The "start" and "end" anchors are located at the origin point of the swept shape.
+//   shape = back_half(right_half(star(n=5,id=5,od=10)),y=-1);
+//   path = arc(angle=[0,180],d=30);
+//   path_sweep(shape,path,method="natural"){
+//     attach(["start-centroid","end-centroid"]) anchor_arrow(s=5);
+//   }
+// Example(Med,NoScales,VPR=[78.1,0,43.2],VPT=[2.18042,-0.485127,1.90371],VPD=74.4017): Note that the "start" anchors are backwards compared to the direction of the sweep, so you have to attach the TOP to align the shape with its ends.  
+//   shape = back_half(right_half(star(n=5,id=5,od=10)),y=-1);
+//   path = arc(angle=[0,180],d=30);
+//   path_sweep(shape,path,method="natural")
+//     recolor("red"){
+//       attach("start",TOP) stroke([path3d(shape[0])],width=.5);
+//       attach("end") stroke([path3d(last(shape))],width=.5);       
+//     }
+
 
 module path_sweep(shape, path, method="incremental", normal, closed, twist=0, twist_by_length=true, scale=1, scale_by_length=true,
                     symmetry=1, last_normal, tangent, uniform=true, relaxed=false, caps, style="min_edge", convexity=10,
                     anchor="origin",cp="centroid",spin=0, orient=UP, atype="hull",profiles=false,width=1)
 {
-    dummy = assert(is_region(shape) || is_path(shape,2), "shape must be a 2D path or region");
+    dummy = assert(is_region(shape) || is_path(shape,2), "shape must be a 2D path or region")
-    vnf = path_sweep(shape, path, method, normal, closed, twist, twist_by_length, scale, scale_by_length,
+            assert(in_list(atype, _ANCHOR_TYPES), "Anchor type must be \"hull\" or \"intersect\"");
-                    symmetry, last_normal, tangent, uniform, relaxed, caps, style);
+    transforms = path_sweep(shape, path, method, normal, closed, twist, twist_by_length, scale, scale_by_length,
-
+                            symmetry, last_normal, tangent, uniform, relaxed, caps, style, transforms=true);
+    vnf = sweep(is_path(shape)?clockwise_polygon(shape):shape, transforms, closed=false, caps=caps,style=style);
+    shapecent = point3d(centroid(shape));
+    $transforms = transforms;
+    anchors = closed ? []
+            :
+              [
+                transform_anchor("start", transforms[0], invert=true), 
+                transform_anchor("end", last(transforms)),
+                transform_anchor("start-centroid", transforms[0]*move(shapecent), invert=true),
+                transform_anchor("end-centroid", last(transforms)*move(shapecent))
+    ];
     if (profiles){
-        assert(in_list(atype, _ANCHOR_TYPES), "Anchor type must be \"hull\" or \"intersect\"");
-        tran = path_sweep(shape, path, method, normal, closed, twist, twist_by_length, scale, scale_by_length, 
-                          symmetry, last_normal, tangent, uniform, relaxed,transforms=true);
         rshape = is_path(shape) ? [path3d(shape)]
                                 : [for(s=shape) path3d(s)];
-        attachable(anchor,spin,orient, vnf=vnf, extent=atype=="hull", cp=cp) {
+        attachable(anchor,spin,orient, vnf=vnf, extent=atype=="hull", cp=cp, anchors=anchors) {
-            for(T=tran) stroke([for(part=rshape)apply(T,part)],width=width);
+            for(T=transforms) stroke([for(part=rshape)apply(T,part)],width=width);
             children();
         }
     }
     else
-      vnf_polyhedron(vnf,convexity=convexity,anchor=anchor, spin=spin, orient=orient, atype=atype, cp=cp)
+      attachable(anchor,spin,orient,vnf=vnf,extent=atype=="hull", cp=cp,anchors=anchors){
+          vnf_polyhedron(vnf,convexity=convexity);
           children();
+      }
 }