#1153 New fillet command for 2D CAD supporting both bevel and chamfer

src/blenderbim/blenderbim/bim/module/cad/__init__.py

@@ -22,6 +22,7 @@ from . import operator, workspace
 classes = (
     operator.CadTrimExtend,
     operator.CadMitre,
+    operator.CadFillet,
     workspace.CadHotkey,
 )
 

src/blenderbim/blenderbim/bim/module/cad/operator.py

@@ -17,7 +17,9 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
+import math
 import bmesh
+import mathutils
 import blenderbim.tool as tool
 
 messages = {
@@ -75,7 +77,7 @@ class CadTrimExtend(bpy.types.Operator):
 
 class CadMitre(bpy.types.Operator):
     bl_idname = "bim.cad_mitre"
-    bl_label = "CAD Trim / Extend"
+    bl_label = "CAD Mitre"
 
     @classmethod
     def poll(cls, context):
@@ -117,3 +119,89 @@ class CadMitre(bpy.types.Operator):
         bmesh.update_edit_mesh(me, loop_triangles=True)
 
         return {"FINISHED"}
+
+
+class CadFillet(bpy.types.Operator):
+    bl_idname = "bim.cad_fillet"
+    bl_label = "CAD Fillet"
+    bl_options = {"REGISTER", "UNDO"}
+    resolution: bpy.props.IntProperty(name="Arc Resolution", min=0, default=1)
+    radius: bpy.props.FloatProperty(name="Radius", default=0.1)
+
+    @classmethod
+    def poll(cls, context):
+        obj = context.active_object
+        return obj and obj.type == "MESH" and context.mode == "EDIT_MESH"
+
+    def draw(self, context):
+        layout = self.layout
+        for prop in self.__class__.__annotations__.keys():
+            layout.prop(self, prop)
+
+    def execute(self, context):
+        if bpy.context.mode != "EDIT_MESH":
+            return {"CANCELLED"}
+        obj = bpy.context.active_object
+        cursor = obj.matrix_world.inverted() @ bpy.context.scene.cursor.location
+        mesh = obj.data
+        bm = bmesh.from_edit_mesh(mesh)
+        selected_edges = [e for e in bm.edges if e.select]
+        if len(selected_edges) != 2:
+            return {"CANCELLED"}
+
+        # Assume the user has selected two edges sharing a vert, but merge verts
+        # just in case the vertex is coincident but not shared.
+        all_verts = list(set(selected_edges[0].verts) | set(selected_edges[1].verts))
+        bmesh.ops.remove_doubles(bm, verts=all_verts, dist=1e-4)
+
+        # Subdivide one of the edges to give us an extra vert to play with
+        # without damaging any faces that already exist.
+        cut = bmesh.ops.bisect_edges(bm, edges=[selected_edges[1]], cuts=1)
+        bm.edges.index_update()
+        bmesh.update_edit_mesh(mesh)
+
+        is_wire = selected_edges[0].is_wire
+
+        # Recover the original intention of the selected edges after our bisect operation
+        cut_edges = cut["geom_split"][1:]
+        selected_edges = [e for e in bm.edges if e.select and e not in cut_edges]
+        if set(selected_edges[0].verts) & set(cut_edges[0].verts):
+            selected_edges.append(cut_edges[0])
+        elif set(selected_edges[0].verts) & set(cut_edges[1].verts):
+            selected_edges.append(cut_edges[1])
+
+        # Calculate the distance to slide each edge to make space for the fillet arc
+        shared_vert = list(set(selected_edges[0].verts) & set(selected_edges[1].verts))[0]
+        v1 = selected_edges[0].other_vert(shared_vert)
+        v2 = selected_edges[1].other_vert(shared_vert)
+        dir1 = (v1.co - shared_vert.co).normalized()
+        dir2 = (v2.co - shared_vert.co).normalized()
+        edge_angle = dir1.angle(dir2)
+        slide_distance = self.radius / math.tan(edge_angle / 2)
+
+        angle = math.pi - edge_angle
+        fillet_v1 = shared_vert.co + (dir1 * slide_distance)
+        fillet_v2 = shared_vert.co + (dir2 * slide_distance)
+
+        normal = mathutils.geometry.normal([v1.co, shared_vert.co, v2.co])
+
+        center = mathutils.geometry.intersect_line_line(
+            fillet_v1, fillet_v1 + normal.cross(dir1), fillet_v2, fillet_v2 + normal.cross(dir2)
+        )[0]
+
+        v = bm.verts.new(fillet_v1)
+        steps = self.resolution * 4 if self.resolution else 1
+        spin = bmesh.ops.spin(bm, geom=[v], axis=normal, cent=center, steps=steps, angle=angle)
+
+        bmesh.ops.pointmerge(bm, verts=[shared_vert, v], merge_co=v.co)
+        bmesh.ops.pointmerge(bm, verts=[v2, spin["geom_last"][0]], merge_co=spin["geom_last"][0].co)
+
+        # If faces are involved, then the chamfer edge protects existing faces from the newly created fillet.
+        # If no faces are involved, we delete the chamfer edge.
+        if is_wire:
+            chamfer_edge = [e for e in bm.edges if shared_vert in e.verts and v2 in e.verts][0]
+            bm.edges.remove(chamfer_edge)
+
+        bmesh.update_edit_mesh(mesh)
+        mesh.update()
+        return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/cad/workspace.py

@@ -37,6 +37,7 @@ class CadTool(WorkSpaceTool):
     bl_keymap = (
         ("bim.cad_hotkey", {"type": "E", "value": "PRESS", "shift": True}, {"properties": [("hotkey", "S_E")]}),
         ("bim.cad_hotkey", {"type": "T", "value": "PRESS", "shift": True}, {"properties": [("hotkey", "S_T")]}),
+        ("bim.cad_fillet", {"type": "F", "value": "PRESS", "shift": True}, {"properties": [("hotkey", "S_F")]}),
     )
 
     def draw_settings(context, layout, tool):
@@ -44,6 +45,14 @@ class CadTool(WorkSpaceTool):
         row.label(text="", icon="EVENT_SHIFT")
         row.label(text="Extend / Trim", icon="EVENT_E")
 
+        row = layout.row(align=True)
+        row.label(text="", icon="EVENT_SHIFT")
+        row.label(text="Mitre", icon="EVENT_T")
+
+        row = layout.row(align=True)
+        row.label(text="", icon="EVENT_SHIFT")
+        row.label(text="Fillet", icon="EVENT_F")
+
 
 class CadHotkey(bpy.types.Operator):
     bl_idname = "bim.cad_hotkey"