Thin Extrude: walls of a set thickness along sketch curves (#721) (#991)

Thin Extrude builds walls of a set thickness along sketch curves, open chains and closed loops, with the wall centred, inside, outside or on both sides at two thicknesses. Saved under format 20 (thin on an Extrude); an extrude without thin saves as before. Closes #721.

crates/doc/src/feature_walk_tests/fixtures.rs

@@ -36,6 +36,11 @@ pub(super) fn fixtures() -> Vec<(&'static str, Value)> {
         ("sketch", json!({"type": "sketch", "plane": plane("sketch"), "sketch": sk.clone()})),
         ("sketch_along_path", json!({"type": "sketch", "plane": along("sketch"), "sketch": sk})),
         ("extrude", json!({"type": "extrude", "sketch": 1, "profiles": {"type": "all"}, "extent": extent("extrude")})),
+        (
+            "extrude_thin",
+            json!({"type": "extrude", "sketch": 1, "profiles": {"type": "all"}, "extent": extent("thin"),
+                "thin": {"curves": ["c1"], "thickness": "thin.thickness", "side": "two_sides", "thickness2": "thin.thickness2"}}),
+        ),
         (
             "revolve",
             json!({"type": "revolve", "sketch": 1, "profiles": {"type": "all"}, "axis": {"type": "world", "axis": "X"}, "angle": "revolve.angle", "angle2": "revolve.angle2"}),
@@ -158,7 +163,7 @@ pub(super) fn with_refs(name: &str, mut v: Value) -> Value {
     let o = [0, 0, 0];
     let tool = json!({"body": "B", "point": o});
     let extra = match name {
-        "extrude" | "revolve" | "sweep" | "pipe" | "coil" | "thicken" => json!({"targets": ["B"]}),
+        "extrude" | "extrude_thin" | "revolve" | "sweep" | "pipe" | "coil" | "thicken" => json!({"targets": ["B"]}),
         "fillet_constant" | "fillet_chord" | "fillet_curvature" | "fillet_variable" | "fillet_spline" | "chamfer" | "shell" | "draft"
         | "offset_face" | "delete_face" | "replace_face" | "sheet_flange" | "sheet_hem" | "sheet_unfold" | "boss" | "lip" | "snap_fit" | "rest"
         | "surface_offset" => {

crates/doc/src/feature_walk_tests/golden_exprs.txt

@@ -16,6 +16,16 @@ extrude
     Taper angle = extrude.taper (Angle)
     To offset = extrude.to_offset (Length)
   expressions: extrude.distance, extrude.distance2, extrude.start_offset, extrude.taper, extrude.to_offset
+extrude_thin
+  inputs:
+    Distance = thin.distance (Length)
+    Distance 2 = thin.distance2 (Length)
+    Start offset = thin.start_offset (Length)
+    Taper angle = thin.taper (Angle)
+    To offset = thin.to_offset (Length)
+    Thickness = thin.thickness (Length)
+    Thickness 2 = thin.thickness2 (Length)
+  expressions: thin.distance, thin.distance2, thin.start_offset, thin.taper, thin.to_offset, thin.thickness, thin.thickness2
 revolve
   inputs:
     Angle = revolve.angle (Angle)

crates/doc/src/feature_walk_tests/golden_refs.txt

@@ -7,6 +7,10 @@ extrude
   sketches: [1]
   remap_refs: sketch
   remap_bodies: targets[0]
+extrude_thin
+  sketches: [1]
+  remap_refs: sketch
+  remap_bodies: targets[0]
 revolve
   sketches: [1]
   remap_refs: sketch