Setting a seam in bmesh

Coding Python Support
1

I am trying to set a seam via a BMEdge object and am failing miserably. Am I missing something?

In the following demo script I would have expected to see a cube, twice normal size with all its edges set to be seams. Instead I get a cube twice normal size with no seams set. The script generates no errors when I run it.

Thank you for any suggestions,
- Bob

— demo.py —
import bpy
import bmesh

bpy.ops.mesh.primitive_cube_add()
cube = bpy.context.object

bm = bmesh.new()
bm.from_mesh(cube.data)

Check that some changes get through - the doubling does

for vertex in bm.verts:
vertex.co *= 2.0

But seam setting doesn’t

for edge in bm.edges:
edge.seam = True

bm.to_mesh(cube.data)

2

Works for me, are you sure Seams are enabled in toolshelf, Mesh Display?

You can enable it programmatically like:
cube.data.show_edge_seams = True

1 Like
3

Thank you! That was exactly the problem. Not sure how it got unset, but it was.

4

It might actually be false by default. You usually won’t notice it being turned off however, because the mark seam operator enables it.