I used BRepAlgoAPI_Fuse to stitch to TopoDS_Face's:
BRepAlgoAPI_Fuse fuser(*second_face, *first_face);
after that, I want to know which Edges on the two Faces are not changed, so I don't need to assign a new id to them. But when I query for fuser.Modified(*second_face) or fuser.Modified2(*second_face), they both give nothing. I know it should return me fuser.Shape() as the modified shape. of course, querying for coresponding underlying edges for modified shapes, returns nothing too.
How can I avoid this bug and get the map between the old_edge and new generated edge?
Thank you for your advise!