Changed the FilletPolyLine to be compatible with 0-radius fillets, where it should behave like a normal Polyline

src/build123d/objects_curve.py

@@ -787,20 +787,22 @@ class Helix(BaseEdgeObject):
 
 class FilletPolyline(BaseLineObject):
     """Line Object: Fillet Polyline
-
     Create a sequence of straight lines defined by successive points that are filleted
     to a given radius.
 
     Args:
         pts (VectorLike | Iterable[VectorLike]): sequence of two or more points
-        radius (float | Iterable[float]): radius to fillet at each vertex or a single value for all vertices
+        radius (float | Iterable[float]): radius to fillet at each vertex or a single value for all vertices.
+            A radius of 0 will create a sharp corner (vertex without fillet).
+
         close (bool, optional): close end points with extra Edge and corner fillets.
             Defaults to False
+
         mode (Mode, optional): combination mode. Defaults to Mode.ADD
 
     Raises:
         ValueError: Two or more points not provided
-        ValueError: radius must be positive
+        ValueError: radius must be non-negative
     """
 
     _applies_to = [BuildLine._tag]
@@ -812,9 +814,9 @@ class FilletPolyline(BaseLineObject):
         close: bool = False,
         mode: Mode = Mode.ADD,
     ):
+
         context: BuildLine | None = BuildLine._get_context(self)
         validate_inputs(context, self)
-
         points = flatten_sequence(*pts)
 
         if len(points) < 2:
@@ -822,30 +824,35 @@ class FilletPolyline(BaseLineObject):
 
         if isinstance(radius, (int, float)):
             radius_list = [radius] * len(points)  # Single radius for all points
+
         else:
             radius_list = list(radius)
             if len(radius_list) != len(points) - int(not close) * 2:
                 raise ValueError(
                     f"radius list length ({len(radius_list)}) must match angle count ({ len(points) - int(not close) * 2})"
                 )
+
         for r in radius_list:
-            if r <= 0:
+            if r < 0:
-                raise ValueError(f"radius {r} must be positive")
+                raise ValueError(f"radius {r} must be non-negative")
 
         lines_pts = WorkplaneList.localize(*points)
-
         # Create the polyline
+
         new_edges = [
             Edge.make_line(lines_pts[i], lines_pts[i + 1])
             for i in range(len(lines_pts) - 1)
         ]
+
         if close and (new_edges[0] @ 0 - new_edges[-1] @ 1).length > 1e-5:
             new_edges.append(Edge.make_line(new_edges[-1] @ 1, new_edges[0] @ 0))
+
         wire_of_lines = Wire(new_edges)
 
         # Create a list of vertices from wire_of_lines in the same order as
         # the original points so the resulting fillet edges are ordered
         ordered_vertices = []
+
         for pnts in lines_pts:
             distance = {
                 v: (Vector(pnts) - Vector(*v)).length for v in wire_of_lines.vertices()
@@ -853,46 +860,90 @@ class FilletPolyline(BaseLineObject):
             ordered_vertices.append(sorted(distance.items(), key=lambda x: x[1])[0][0])
 
         # Fillet the corners
-
         # Create a map of vertices to edges containing that vertex
         vertex_to_edges = {
             v: [e for e in wire_of_lines.edges() if v in e.vertices()]
             for v in ordered_vertices
         }
 
-        # For each corner vertex create a new fillet Edge
+        # For each corner vertex create a new fillet Edge (or keep as vertex if radius is 0)
         fillets = []
+
         for i, (vertex, edges) in enumerate(vertex_to_edges.items()):
             if len(edges) != 2:
                 continue
+            current_radius = radius_list[i - int(not close)]
+
+            if current_radius == 0:
+                # For 0 radius, store the vertex as a marker for a sharp corner
+                fillets.append(None)
+
+            else:
                 other_vertices = {ve for e in edges for ve in e.vertices() if ve != vertex}
                 third_edge = Edge.make_line(*[v for v in other_vertices])
                 fillet_face = Face(Wire(edges + [third_edge])).fillet_2d(
-                radius_list[i - int(not close)], [vertex]
+                    current_radius, [vertex]
                 )
                 fillets.append(fillet_face.edges().filter_by(GeomType.CIRCLE)[0])
 
         # Create the Edges that join the fillets
         if close:
-            interior_edges = [
+            interior_edges = []
-                Edge.make_line(fillets[i - 1] @ 1, fillets[i] @ 0)
-                for i in range(len(fillets))
-            ]
-            end_edges = []
-        else:
-            interior_edges = [
-                Edge.make_line(fillets[i] @ 1, f @ 0) for i, f in enumerate(fillets[1:])
-            ]
-            end_edges = [
-                Edge.make_line(wire_of_lines @ 0, fillets[0] @ 0),
-                Edge.make_line(fillets[-1] @ 1, wire_of_lines @ 1),
-            ]
 
-        new_wire = Wire(end_edges + interior_edges + fillets)
+            for i in range(len(fillets)):
+                prev_idx = i - 1
+                curr_idx = i
+                # Determine start and end points
+                if fillets[prev_idx] is None:
+                    start_pt = ordered_vertices[prev_idx]
+                else:
+                    start_pt = fillets[prev_idx] @ 1
+
+                if fillets[curr_idx] is None:
+                    end_pt = ordered_vertices[curr_idx]
+                else:
+                    end_pt = fillets[curr_idx] @ 0
+                interior_edges.append(Edge.make_line(start_pt, end_pt))
+
+            end_edges = []
+
+        else:
+            interior_edges = []
+            for i in range(len(fillets) - 1):
+                curr_idx = i
+                next_idx = i + 1
+                # Determine start and end points
+                if fillets[curr_idx] is None:
+                    start_pt = ordered_vertices[curr_idx + 1]  # +1 because first vertex has no fillet
+                else:
+                    start_pt = fillets[curr_idx] @ 1
+
+                if fillets[next_idx] is None:
+                    end_pt = ordered_vertices[next_idx + 1]
+                else:
+                    end_pt = fillets[next_idx] @ 0
+                interior_edges.append(Edge.make_line(start_pt, end_pt))
+
+            # Handle end edges
+            if fillets[0] is None:
+                start_edge = Edge.make_line(wire_of_lines @ 0, ordered_vertices[1])
+            else:
+                start_edge = Edge.make_line(wire_of_lines @ 0, fillets[0] @ 0)
+
+            if fillets[-1] is None:
+                end_edge = Edge.make_line(ordered_vertices[-2], wire_of_lines @ 1)
+            else:
+                end_edge = Edge.make_line(fillets[-1] @ 1, wire_of_lines @ 1)
+            end_edges = [start_edge, end_edge]
+
+        # Filter out None values from fillets (these are 0-radius corners)
+        actual_fillets = [f for f in fillets if f is not None]
+        new_wire = Wire(end_edges + interior_edges + actual_fillets)
 
         super().__init__(new_wire, mode=mode)
 
 
+
 class JernArc(BaseEdgeObject):
     """Line Object: Jern Arc