Vertex groups belong to Object?

Hi there,

I was reorganizing some old character models from 2.49.

While doing this I recognized that when I append a mesh (skin of character) the vertex groups are gone. This is a bit annoying as it was really a lot of work to establish them as they are.

First I thought it is a problem of converting from 2.49 to 2.65.
So I appended the full object rather than just the mesh.
On this object the vertex groups are present.

Then switched my new characters mesh (new skin mesh object) to the appended mesh. The vertex groups are gone.

I did some test:

  • added a cube
  • copied the cube with linked mesh <alt+d>
  • edited the mesh of one cube
  • added a vertex group “Group”
  • assigned a few vertex to it

Check the second cube:

  • the vertex group is not present

Even when I switch to any other mesh, the vertex groups stay the same with the object.

This let me conclude the vertex group is part of the object not part of the mesh.

But how does the vertex know what group it belongs to it?

Some further investigations:

  • add the vertex group “Group” to the second cube without assigning it to vertices
    => now you can select the vertices as assigned with the first cube

It seems the vertices know the groups by name.
E.g. vertex A belongs to group “Group” and vertex B belongs to no group at all

This let me conclude the vertices (from mesh) have an association to the group names (less the group itself).

So you need the association to vertex group in Mesh and in Object.

Attention: In difference to adding groups to objects, “remove” removes the group name from the vertices as well.
So if you want top skip a vertex group name from an object, better assign a different mesh to it. Otherwise the vertices of the mesh loose there relationship to the group name.

How do I get my vertex groups back?
Well I need the vertex groups at the skin mesh object that I already have (but does not have the groups). As I fixed some material/UV/vertex issues already - How can I get the original vertex group association on that mesh and on the object?

I found one solution:
Parent … Armature Deform/With Empty Groups
This option seems to fit very well, as I need the group names matching the bone names of the armature.

Attention: Be careful the other Armature Deform options reassign the groups on the vertices and destroy the original groups assignment on the vertex.

[Edit:] this solution does not work. It seems the vertex store the index of the vertex group. But auto assign does not necessarily create the same order as required.

You can copy the object vertex groups to another object when the mesh is linked. do
<space>Copy Vertex Group to linked

Did anyone had similar experiences?

I always use the “Append/Object” method!

1 Like

The “copy vertex group to linked” command do the trick for my problem! Thanks! Is there a way to navigate to that function without using space bar?

Also, what do you mean by Append/Object method?

file->append->choose a blend-> select any object/material/scene you want to append