revamp extruded region attachables and apply to linear_sweep.

attachments.scad

@@ -1515,10 +1515,10 @@ function _attach_transform(anchor, spin, orient, geom, p) =
 
 
 function _get_cp(geom) =
+    
     let(cp=select(geom,-3))
     is_vector(cp) ? cp
   : let(
-       f=echo(type=geom[0]),
         type = in_list(geom[0],["vnf_extent","vnf_isect"]) ? "vnf"
              : in_list(geom[0],["rgn_extent","rgn_isect"]) ? "path"
              : in_list(geom[0],["xrgn_extent","xrgn_isect"]) ? "xpath"
@@ -1549,20 +1549,22 @@ function _get_cp(geom) =
 //   anchor = Vector or named anchor string.
 //   geom = The geometry description of the shape.
 function _find_anchor(anchor, geom) =
+    is_string(anchor)? (  
+          anchor=="origin"? [anchor, CENTER, UP, 0]
+        : let(
+              anchors = last(geom),
+              found = search([anchor], anchors, num_returns_per_match=1)[0]
+          )
+          assert(found!=[], str("Unknown anchor: ",anchor))
+          anchors[found]
+    ) :
     let( 
         cp = _get_cp(geom),
         offset_raw = select(geom,-2),
         offset = [for (i=[0:2]) anchor[i]==0? 0 : offset_raw[i]],  // prevents bad centering.
-        anchors = last(geom),
         type = geom[0]
     )
-    is_string(anchor)? (  
+    assert(is_vector(anchor),str("Invalid anchor: anchor=",anchor))
-          anchor=="origin"? [anchor, CENTER, UP, 0]
-        : let(found = search([anchor], anchors, num_returns_per_match=1)[0])
-          assert(found!=[], str("Unknown anchor: ",anchor))
-          anchors[found]
-    ) : 
-    assert(is_vector(anchor),str("anchor=",anchor))
     let(anchor = point3d(anchor))
     anchor==CENTER? [anchor, cp, UP, 0] :
     let(
@@ -1725,8 +1727,7 @@ function _find_anchor(anchor, geom) =
     ) : type == "rgn_isect"? ( //region
         assert(anchor.z==0, "The Z component of an anchor for a 2D shape must be 0.")
         let(
-            rgn_raw = move(-point2d(cp), p=geom[1]),
+            rgn = force_region(move(-point2d(cp), p=geom[1])),
-            rgn = is_region(rgn_raw)? rgn_raw : [rgn_raw],
             anchor = point2d(anchor),
             isects = [
                 for (path=rgn, t=triplet(path,true)) let(
@@ -1753,68 +1754,27 @@ function _find_anchor(anchor, geom) =
         let(
             rgn = force_region(geom[1]),
             anchor = point2d(anchor),
-            m = rot(from=anchor, to=RIGHT) * move(-[cp.x, cp.y, 0]),
+            rpts = rot(from=anchor, to=RIGHT, p=flatten(rgn)),
-            rpts = apply(m, flatten(rgn)),
             maxx = max(column(rpts,0)),
-            idxs = [for (i = idx(rpts)) if (approx(rpts[i].x, maxx)) i],
+            ys = [for (pt=rpts) if (approx(pt.x, maxx)) pt.y],            
-            miny = min([for (i=idxs) rpts[i].y]),
-            maxy = max([for (i=idxs) rpts[i].y]),
-            midy = (miny+maxy)/2,
-            pos = point2d(cp) + rot(from=RIGHT, to=anchor, p=[maxx,midy])
-        ) [anchor, pos, anchor, 0]
-    ) : type == "xrgn_isect"? ( //region
-        assert(in_list(anchor.z,[-1,0,1]), "The Z component of an anchor for an extruded 2D shape must be -1, 0, or 1.")
-        let(
-            rgn_raw = move(-point2d(cp), p=geom[1]),
-            l = geom[2],
-            rgn = is_region(rgn_raw)? rgn_raw : [rgn_raw],
-            anchor = point3d(anchor),
-            xyanch = point2d(anchor)
-        ) approx(xyanch,[0,0])? [anchor, [0,0,anchor.z*l/2], unit(anchor,UP), 0] :
-        let(
-            isects = [
-                for (path=rgn, t=triplet(path,true)) let(
-                    seg1 = [t[0],t[1]],
-                    seg2 = [t[1],t[2]],
-                    isect = line_intersection([[0,0],xyanch], seg1, RAY, SEGMENT),
-                    n = is_undef(isect)? [0,1] :
-                        !approx(isect, t[1])? line_normal(seg1) :
-                        unit((line_normal(seg1)+line_normal(seg2))/2,[0,1]),
-                    n2 = vector_angle(xyanch,n)>90? -n : n
-                )
-                if(!is_undef(isect) && !approx(isect,t[0]))
-                [norm(isect), isect, n2]
-            ],
-            maxidx = max_index(column(isects,0)),
-            isect = isects[maxidx],
-            pos = point3d(cp) + point3d(isect[1]) + unit([0,0,anchor.z],CENTER)*l/2,
-            xyvec = unit(isect[2],[0,1]),
-            vec = unit((point3d(xyvec)+UP*anchor.z)/2,UP),
-            oang = approx(xyvec, [0,0])? 0 : atan2(xyvec.y, xyvec.x) + 90
-        ) [anchor, pos, vec, oang]
-    ) : type == "xrgn_extent"? ( //region
-        assert(in_list(anchor.z,[-1,0,1]), "The Z component of an anchor for an extruded 2D shape must be -1, 0, or 1.")
-        let(
-            rgn = force_region(geom[1]),
-            l = geom[2],
-            anchor = point3d(anchor),
-            xyanch = point2d(anchor),
-            m = (
-                approx(xyanch,[0,0])? [[1,0,0],[0,1,0],[0,0,1]] :
-                rot(from=xyanch, to=RIGHT, planar=true)
-            ) * move(-[cp.x, cp.y]),
-            rpts = apply(m, flatten(rgn)),
-            maxx = max(column(rpts,0)),
-            idxs = [for (i = idx(rpts)) if (approx(rpts[i].x, maxx)) i],
-            ys = [for (i=idxs) rpts[i].y],
             midy = (min(ys)+max(ys))/2,
-            xypos = point2d(cp) + (
+            pos = rot(from=RIGHT, to=anchor, p=[maxx,midy])
-                approx(xyanch,[0,0])? [0,0] :
+        ) [anchor, pos, unit(anchor), 0]
-                rot(from=RIGHT, to=xyanch, p=[maxx,midy])
+    ) : type=="xrgn_extent" || type=="xrgn_isect" ? (  // extruded region
-            ),
+        assert(in_list(anchor.z,[-1,0,1]), "The Z component of an anchor for an extruded 2D shape must be -1, 0, or 1.")
-            pos = point3d(xypos) + unit([0,0,anchor.z],CENTER)*l/2,
+        let(
-            vec = unit((point3d(xyanch)+UP*anchor.z)/2,UP)
+            anchor_xy = point2d(anchor),
-        ) [anchor, pos, vec, oang]
+            L = geom[2]
+        )
+        approx(anchor_xy,[0,0]) ? [anchor, up(anchor.z*L/2,cp), anchor, oang] :
+        let(
+            newgeom = list_set(geom, [0,len(geom)-3], [substr(geom[0],1), point2d(cp)]),
+            result2d = _find_anchor(anchor_xy, newgeom),
+            pos = point3d(result2d[1], cp.z+anchor.z*L/2),
+            vec = unit(point3d(result2d[2], anchor.z),UP),
+            oang = atan2(vec.y,vec.x) + 90
+        )
+        [anchor, pos, vec, oang]
     ) :
     assert(false, "Unknown attachment geometry type.");
 

regions.scad

@@ -612,7 +612,7 @@ function region_parts(region) =
 //   style = The style to use when triangulating the surface of the object.  Valid values are `"default"`, `"alt"`, or `"quincunx"`.
 //   convexity = Max number of surfaces any single ray could pass through.  Module use only.
 //   anchor = Translate so anchor point is at origin (0,0,0).  See [anchor](attachments.scad#anchor).  Default: `"origin"`
-//   anchor_isect = If true, anchoring it performed by finding where the anchor vector intersects the swept shape.  Default: false
+//   atype = Set to "hull" or "intersect" to select anchor type.  Default: "hull"
 //   cp = Centerpoint for determining intersection anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 //   spin = Rotate this many degrees around the Z axis after anchor.  See [spin](attachments.scad#spin).  Default: `0`
 //   orient = Vector to rotate top towards, after spin.  See [orient](attachments.scad#orient).  Default: `UP`
@@ -637,7 +637,8 @@ function region_parts(region) =
 //   mrgn = union(rgn1,rgn2);
 //   orgn = difference(mrgn,rgn3);
 //   linear_sweep(orgn,height=20,convexity=16) show_anchors();
-module linear_sweep(region, height=1, center, twist=0, scale=1, slices, maxseg, style="default", convexity, anchor_isect=false, spin=0, orient=UP, cp="centroid", anchor="origin", atype="hull") {
+module linear_sweep(region, height=1, center, twist=0, scale=1, slices, maxseg, style="default", convexity,
+                    spin=0, orient=UP, cp="centroid", anchor="origin", atype="hull") {
     region = force_region(region);
     dummy=assert(is_region(region),"Input is not a region");
     anchor = center ? "zcenter" : anchor;

skin.scad

@@ -154,7 +154,7 @@
 //   spin = Rotate this many degrees around Z axis after anchor.  Default: 0
 //   orient = Vector to rotate top towards after spin 
 //   atype = Select "hull" or "intersect anchor types. Default: "hull"
-//   cp = set centerpoint for anchor computation.  Default: "centroid"
+//   cp = Centerpoint for determining "intersect" anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 //   style = vnf_vertex_array style.  Default: "min_edge"
 // Example:
 //   skin([octagon(4), circle($fn=70,r=2)], z=[0,3], slices=10);
@@ -570,7 +570,7 @@ function skin(profiles, slices, refine=1, method="direct", sampling, caps, close
 //   spin = Rotate this many degrees around Z axis after anchor. Default: 0
 //   orient = Vector to rotate top towards after spin  
 //   atype  = Select "hull" or "intersect" anchor types.  Default: "hull"
-//   cp = set centerpoint for anchor computation.  Default: "centroid"
+//   cp = Centerpoint for determining "intersect" anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 // Example(2D): We'll use this shape in several examples
 //   ushape = [[-10, 0],[-10, 10],[ -7, 10],[ -7, 2],[  7, 2],[  7, 7],[ 10, 7],[ 10, 0]];
 //   polygon(ushape);
@@ -949,7 +949,7 @@ function path_sweep(shape, path, method="incremental", normal, closed=false, twi
 //   spin = Rotate this many degrees around Z axis after anchor.  Default: 0
 //   orient = Vector to rotate top towards after spin 
 //   atype = Select "hull" or "intersect" anchor types.  Default: "hull"
-//   cp = set centerpoint for anchor computation.  Default: "centroid"
+//   cp = Centerpoint for determining "intersect" anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 // Example: Sine wave example with self-intersections at each peak.  This would fail with path_sweep(). 
 //   sinewave = [for(i=[-30:10:360*2+30]) [i/40,3*sin(i)]];
 //   path_sweep2d(circle(r=3,$fn=15), sinewave);
@@ -1073,7 +1073,7 @@ function _ofs_face_edge(face,firstlen,second=false) =
 //   spin = Rotate this many degrees around Z axis after anchor. Default: 0
 //   orient = Vector to rotate top towards after spin  (module only)
 //   atype = Select "hull" or "intersect" anchor types.  Default: "hull"
-//   cp = set centerpoint for anchor computation. Default: "centroid"
+//   cp = Centerpoint for determining "intersect" anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 // Example: This is the "sweep-drop" example from list-comprehension-demos.
 //   function drop(t) = 100 * 0.5 * (1 - cos(180 * t)) * sin(180 * t) + 1;
 //   function path(t) = [0, 0, 80 + 80 * cos(180 * t)];

strings.scad

@@ -17,7 +17,7 @@
 // Arguments:
 //   str = string to operate on
 //   pos = starting index of substring, or vector of first and last position.  Default: 0
-//   len = length of substring, or omit it to get the rest of the string.  If len is less than zero the emptry string is returned.  
+//   len = length of substring, or omit it to get the rest of the string.  If len is zero or less then the emptry string is returned.  
 // Example:
 //   substr("abcdefg",3,3);     // Returns "def"
 //   substr("abcdefg",2);       // Returns "cdefg"

vnf.scad

@@ -783,7 +783,7 @@ function _slice_3dpolygons(polys, dir, cuts) =
 //   vnf = A VNF structure, or list of VNF structures.
 //   convexity = Max number of times a line could intersect a wall of the shape.
 //   extent = If true, calculate anchors by extents, rather than intersection.  Default: true.
-//   cp = Centerpoint of VNF to use for anchoring when `extent` is false.  Default: `[0, 0, 0]`
+//   cp = Centerpoint for determining intersection anchors or centering the shape.  Determintes the base of the anchor vector.  Can be "centroid", "mean", "box" or a 3D point.  Default: "centroid"
 //   anchor = Translate so anchor point is at origin (0,0,0).  See [anchor](attachments.scad#anchor).  Default: `"origin"`
 //   spin = Rotate this many degrees around the Z axis after anchor.  See [spin](attachments.scad#spin).  Default: `0`
 //   orient = Vector to rotate top towards, after spin.  See [orient](attachments.scad#orient).  Default: `UP`