Help needed with bmesh.update_edit_mesh()

Coding Python Support
1

Hi,

I’ve trying to get into the Python API. BMesh especially interests me. However I can’t seem to get my head wrapped around the update_edit_mesh() method. I’ve tried writing a piece of code which will take a plane (in EDIT mode) and translate it 10 BU’s along the x-axis (Please excuse the “triviality” of the job to be done - it is merely illustrative…)

Now, I’m calling update_edit_mesh() at the end of each loop iteration. What I expect to see is the mesh updating 10 times - much like 10 frames of animation. However, what I see is only the last frame.

Could you please point out what I am missing? I am not a core programmer, so you might have to be patient with me!

import bpy
import bmesh
import mathutils

plane = bpy.context.object.data # get selected object
bplane = bmesh.from_edit_mesh(plane) # create BMesh in EDIT mode

cv = len(bplane.verts) # get number of vertices

g = 0 # initialise loop counter
while (g < 10):
    for i in range(0, cv): # ...for every vertex...
        bplane.verts[i].co += mathutils.Vector((1, 0, 0)) # add x-translation of 1 BU
            
    g += 1 # increment loop counter
    bmesh.update_edit_mesh(plane, False, False) # update calculations to mesh

I have even tried adding a delay loop within the main loop just to see if its happening too fast - but to no avail. Any assistance would be greatly appreciated. Thanks in advance.

Regards
Anurup

2

scripts run blocking in blender, viewport is refreshed afterwards. If you wanna see the single steps, code an operator that performs one step and click it 10x.

3

Thanks coDEmanX! So I gather there is no way to see the individual “frames”…

4

you could use from_mesh and to_mesh to create a multiple meshes, or maybe use shapekeys if vertex count doesn’t change

5

Thanks again! Will explore the options that you suggested.