How do I get the combined data of all objects in the list?

Archive Python API
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1

I need to get the average value between the selected vertices. I can get it for a single object, but when I try to do it in multi-object editing mode, it fails.

if bpy.context.scene.tool_settings.transform_pivot_point == 'MEDIAN_POINT':
    obj = bpy.context.edit_object
    bm = bmesh.from_edit_mesh(obj.data)
    verts_sel = [v for v in bm.verts if v.select is True]
    verts_co = [v.co for v in verts_sel]
    matrix_select = mathutils.Matrix.Translation(sum(verts_co, mathutils.Vector()) / len(verts_sel))
    ob = obj.matrix_world @ matrix_select

I need it for custom gizmo mode ‘MEDIAN_POINT’.

2

this is one of the annoying things about working with BMesh- there is no built-in way to handle multi-object edit mode. I added a python paper cut asking for a bmesh.from_edit_meshes(context.selected_objects) or something along those lines a long time ago but never got any responses.

what you have to do is create a list of bmeshes for each object and calculate everything that way. it’s annoying boilerplate, but it works.

that last bit is where you’re going to run into problems with multi-edit, because each object has its own transform so you can’t reasonably expect to use N different matrices and apply them all to the same gizmo. It’s better to transform your vert coordinates into world space and then get the median point

for example-

bms = {}
for o in bpy.context.selected_objects:
    bms[o] = bmesh.from_edit_mesh(o.data)

verts = []
for o in bms:
    verts.extend([v.co @ o.matrix_world for v in bms[o].verts if v.select]) 

median_point = sum(verts, mathutils.Vector()) / len(verts)

The nice part about doing it this way is that you end up with a dictionary of bmeshes indexed by their object, so updating the edit mesh is as simple as:

for o in bms:
    bmesh.update_edit_mesh(o.data)
1 Like
3

thanks for your answer, it helped me)

uniques = context.objects_in_mode
bms = {}
for obj in uniques:
    bms[obj] = bmesh.from_edit_mesh(obj.data)
                
verts = []
for ob in bms:
    verts.extend([ob.matrix_world @ v.co  for v in bms[ob].verts if v.select]) 
ob = mathutils.Matrix.Translation(sum(verts, mathutils.Vector()) / len(verts))