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How to mirror weight painting on Blender?

I use Blender 2.66, and I read somewhere that you can mirror the rigging and weight painting with equivalent bones, for example, 'ArmR' with 'ArmL'.

The thing is I am lost on how to do it, I am having troubles with this almost-finished mesh dress where both sides need more weight painting fixes, that I can archive with time, but the thing is I can't never make both sides similar enough, and if I could mirror the weight and rigging would be great.

Is it really possible to do it? Thank you in advance!

Ordem da Rosa * Historical fashion
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Gaia Clary
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Re: How to mirror weight painting on Blender?

[ Edited ]

Reply to LisaMarie McWinnie - view message

to get mirror weighting to work well, your character must be oriented with its face looking in positive or negatvie Y-direction. that is when you use the second life armature, then you have to rotate it by 90 degrees along the z axis, before you can use mirror copy. i think you have to apply rotation as well (not sure).

Then when you are done, for exporting to Second Life, just rotate the character back so that it looks to negative x direction.

Note that the weight tools have been improved a lot in the upcoming Blender 2.68. It should be much easier now to get decent weights done and weight mirroring is one of the topics that have been improved.

The documentation is here:

http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Vertex_Groups/Weight_Paint
http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Vertex_Groups/Weight_Paint_Tools

The documentation should partially work as well for older releases.

the mesh weaver
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Re: How to mirror weight painting on Blender?

Reply to LisaMarie McWinnie - view message

Thanks alot! I will definately try the newer version of Blender.

So its just rotate the mesh and the armature on that direction, and then in the weight painting options select 'mirror X'?

Ordem da Rosa * Historical fashion
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Re: How to mirror weight painting on Blender?

[ Edited ]

Reply to LisaMarie McWinnie - view message

So its just rotate the mesh and the armature on that direction, and then in the weight painting options select 'mirror X'?

"X-axis mirror won't reflect what you already have, it will reflect what you do from that point on. In a new blend file, tab into edit mode on the default cube. Click on x-axis mirror, then grab a vert in positive x side and move it around. You should see the corresponding verts on the other side move also."

- So yes it is one possibility to 'start' that way, when editing to keep tje paintings on both sides the same.

 - Another more effective way (imho) is to use the Mirror-Modifier.

  Split your model into a half, and delete one of the halfs.  Then you add the "mirror-modifier"
  http://wiki.blender.org/index.php/Doc:2.6/Manual/Modifiers/Generate/Mirror
  This one will not only mirror the mesh, it will also perfectly mirror all weights and adjustments that are being made
  to them. And it will do so on the fly / while editing.
  It also mirrors seams and everythig else. And even the posing will be emulated correctly.
  I.e.  If you mirror your dress and you go into posemode with the skeleton and do movements to test the dress, you
  will notice that the mirrored side perfectly 'only' reacts to the bones of the opposed side.
  (instead of just also moving along when you move bones on the side of the original half mesh)
  It will do this as long as the group names and bone names are conclusive and within the blender name conventions
  (which is correct for the most downloadable skeletons for the SL avatar)

Working with the mirror modifier is a breeze, when you got to know it : )


Once you are done, you apply the mirror modifier and make the model become 'one'.
(as long as your model is symetric this is the best way to easily work on weights for both sides of a model,
non-symetric works too but u might need to re-edit the parts later that are 'not equal' on both sides- which isn't a big hurdle either : ) ) 




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