Feature: support creation of elements on n-gons (i.e convert ngons to…

… quads)

- Works by creating tiny initial inset if face is an ngon and removing unnecessary verts.

btools/core/balcony/balcony_types.py

@@ -11,8 +11,8 @@
     valid_ngon,
     filter_geom,
     create_face,
+    ngon_to_quad,
     get_top_faces,
-    popup_message,
     add_faces_to_map,
     calc_face_dimensions,
 )
@@ -22,11 +22,9 @@ def create_balcony(bm, faces, prop):
     """Generate balcony geometry
     """
     for f in faces:
-        if not valid_ngon(f):
-            popup_message("Balcony creation not supported for non-rectangular n-gon!", "Ngon Error")
-            return False
-
         f.select = False
+        if not valid_ngon(f):
+            ngon_to_quad(bm, f)
 
         normal = f.normal.copy()
         f = create_balcony_split(bm, f, prop)

btools/core/door/door_types.py

@@ -14,7 +14,7 @@
     validate,
     local_xyz,
     valid_ngon,
-    popup_message,
+    ngon_to_quad,
     map_new_faces,
     get_top_edges,
     get_top_faces,
@@ -32,11 +32,10 @@ def create_door(bm, faces, prop):
     """Create door from face selection
     """
     for face in faces:
+        face.select = False
         if not valid_ngon(face):
-            popup_message("Door creation not supported non-rectangular n-gon!", "Ngon Error")
-            return False
+            ngon_to_quad(bm, face)
 
-        face.select = False
         clamp_count(calc_face_dimensions(face)[0], prop.frame_thickness * 2, prop)
         array_faces = subdivide_face_horizontally(
             bm, face, widths=[prop.size_offset.size.x] * prop.count

btools/core/multigroup/multigroup_types.py

@@ -12,6 +12,7 @@
     validate,
     local_xyz,
     valid_ngon,
+    ngon_to_quad,
     get_top_faces,
     get_top_edges,
     popup_message,
@@ -40,11 +41,9 @@ def create_multigroup(bm, faces, prop):
         prop.components = re.sub("[^d|w|]", "", prop.components)
 
     for face in faces:
-        if not valid_ngon(face):
-            popup_message("Multigroup creation not supported for non-rectangular n-gon!", "Ngon Error")
-            return False
-
         face.select = False
+        if not valid_ngon(face):
+            ngon_to_quad(bm, face)
 
         array_faces = subdivide_face_horizontally(bm, face, widths=[prop.size_offset.size.x]*prop.count)
         for aface in array_faces:

btools/core/window/window_types.py

@@ -14,7 +14,7 @@
     valid_ngon,
     sort_faces,
     sort_edges,
-    popup_message,
+    ngon_to_quad,
     get_top_edges,
     get_top_faces,
     map_new_faces,
@@ -35,15 +35,15 @@ def create_window(bm, faces, prop):
     """Generate a window
     """
     for face in faces:
+        face.select = False
         if not valid_ngon(face):
-            popup_message("Window creation not supported for non-rectangular n-gon", "Ngon Error")
-            return False
+            ngon_to_quad(bm, face)
 
-        face.select = False
         clamp_count(calc_face_dimensions(face)[0], prop.frame_thickness * 2, prop)
         array_faces = subdivide_face_horizontally(bm, face, widths=[prop.size_offset.size.x]*prop.count)
         for aface in array_faces:
             face = create_window_split(bm, aface, prop.size_offset.size, prop.size_offset.offset)
+
             window, arch = create_window_frame(bm, face, prop)
             if prop.type == "RECTANGULAR":
                 fill_window_face(bm, window, prop)

btools/utils/util_mesh.py

@@ -367,3 +367,22 @@ def sort_edges(edges, direction):
 
 def sort_verts(verts, direction):
     return sorted(verts, key=lambda v: direction.dot(v.co))
+
+
+def ngon_to_quad(bm, face):
+    """ Try to convert rectangular ngon to quad
+    Method:
+    - Perform inset.
+    - Dissolve all edges that are created from lone(non-corner) verts.
+    - Dissolve all the lone(non-corner) verts.
+    """
+
+    INSET_EPS = 0.0011
+    bmesh.ops.inset_individual(
+        bm, faces=[face], thickness=INSET_EPS, use_even_offset=True
+    )
+
+    diss_verts = list({loop.vert for loop in face.loops if equal(loop.calc_angle(), math.pi)})
+    diss_edges = list({e for v in diss_verts for e in v.link_edges if e not in face.edges})
+    bmesh.ops.dissolve_edges(bm, edges=diss_edges)
+    bmesh.ops.dissolve_verts(bm, verts=diss_verts)