Merging vertexgroups and preserving their weight values?

Hello folks, new user here.

I’m trying to convert some XPS models into a different format, and in order to do so I must get rid of a lot of unnecessary bones. Rearranging the skeleton is fairly easy, but I can’t find a way to merge the old vertex groups into a single one without destroying their weight values.

I did google for a possible solution before posting here, but no luck so far. Actually I found this to be a pretty recurring question (even on this very forum, but I thought I’d ask anyway) that sistematically goes either ignored or unsolved. I can only hope someone came up with out a solution recently. :stuck_out_tongue:

Thanks for reading.

I must get rid of a lot of unnecessary bones.

For every bone there is associated vertex group on object. When you remove a bone, try removing that vertex group for that bone at the same time. However bone weighing may not come out clean; some of the weighing may be shared with remaining bone or some parts of the mesh may loose controlling bone all together. For the mesh area that lost the controlling bone, you probably need to remove all vertices called out on that vertex group. Fill in the hole. See if you can get away with it.

Sorry, does that mean you’re suggesting to delete part of the mesh, and then rebuild it?

Indeed, and hence my problem: I need to transfer the weight values from the vertexgroups I’m going to delete to the vertexgroups I’m going to keep, in order to keep the rig as it is. I could (and did) try to weightpaint the data manually, but after a few hours I realised that:

a) it takes a lot of time
b) the result is too imprecise, no matter how hard I try. The original rig is excellent and any edit I can do would only bring down the quality.

Though maybe I’ve actually found a solution! There’s a modifier that seems to do exactly what I need, among other things. http://wiki.blender.org/index.php/Doc:2.6/Manual/Modifiers/Modify/Vertex_Weight#Vertex_Weight_Mix_Modifier

After applying that (and deleting the bones and vertexgroups I wanted to get rid of) the model behaves perfectly in Blender, I’m just wondering if it will cause problems with my exporter…

1 Like

Great that Mod is what i was looking for. Only thing i find confusing is which one is the outcome. It seems the outcome is A and B is the target to add. NKind of fuzy in the beginning. But it does the job