utility function for mesh data types

mesh.edge_loops_from_edges(edges=None)

Lets you get edge loops from python either from the entire mesh or from by passing an edge list.

release/scripts/modules/bpy_types.py

@@ -303,7 +303,7 @@ class Mesh(bpy_types.ID):
         edge_face_count_dict = self.edge_face_count_dict
         return [edge_face_count_dict.get(ed.key, 0) for ed in self.edges]
 
-    def edge_loops(self, faces=None, seams=()):
+    def edge_loops_from_faces(self, faces=None, seams=()):
         """
         Edge loops defined by faces
 
@@ -314,7 +314,7 @@ class Mesh(bpy_types.ID):
         return a list of edge key lists
         [ [(0,1), (4, 8), (3,8)], ...]
 
-        optionaly, seams are edge keys that will be removed
+        return a list of edge vertex index lists
         """
 
         OTHER_INDEX = 2, 3, 0, 1 # opposite face index
@@ -379,6 +379,71 @@ class Mesh(bpy_types.ID):
 
         return edge_loops
 
+    def edge_loops_from_edges(self, edges=None):
+        """
+        Edge loops defined by edges
+
+        Takes me.edges or a list of edges and returns the edge loops
+
+        return a list of vertex indices.
+        [ [1, 6, 7, 2], ...]
+
+        closed loops have matching start and end values.
+        """
+        line_polys = []
+        
+        # Get edges not used by a face
+        if edges is None:
+            edges = self.edges
+
+        if not hasattr(edges, "pop"):
+            edges = edges[:]
+
+        edge_dict= dict((ed.key, ed) for ed in self.edges if ed.selected)
+        
+        while edges:
+            current_edge= edges.pop()
+            vert_end, vert_start = current_edge.verts[:]
+            line_poly = [vert_start, vert_end]
+
+            ok = True
+            while ok:
+                ok = False
+                #for i, ed in enumerate(edges):
+                i = len(edges)
+                while i:
+                    i -= 1
+                    ed = edges[i]
+                    v1, v2 = ed.verts
+                    if v1 == vert_end:
+                        line_poly.append(v2)
+                        vert_end = line_poly[-1]
+                        ok = 1
+                        del edges[i]
+                        #break
+                    elif v2 == vert_end:
+                        line_poly.append(v1)
+                        vert_end = line_poly[-1]
+                        ok = 1
+                        del edges[i]
+                        #break
+                    elif v1 == vert_start:
+                        line_poly.insert(0, v2)
+                        vert_start = line_poly[0]
+                        ok = 1
+                        del edges[i]
+                        #break    
+                    elif v2 == vert_start:
+                        line_poly.insert(0, v1)
+                        vert_start = line_poly[0]
+                        ok = 1
+                        del edges[i]
+                        #break
+            line_polys.append(line_poly)
+
+        return line_polys
+
+
 
 class MeshEdge(StructRNA):
     __slots__ = ()

release/scripts/op/uvcalc_follow_active.py

@@ -180,7 +180,7 @@ def extend(obj, operator, EXTEND_MODE):
     #SEAM = me.edges.seam
 
     if EXTEND_MODE == 'LENGTH':
-        edge_loops = me.edge_loops(face_sel, [ed.key for ed in me.edges if ed.seam])
+        edge_loops = me.edge_loops_from_faces(face_sel, [ed.key for ed in me.edges if ed.seam])
         me_verts = me.verts
         for loop in edge_loops:
             looplen = [0.0]