Blender Wont mirror weight Paint

Hi there, im not new on blender, but not an pro too, and i have search alot for my problem but found nothing working,
So my problem is, i have a model and want an armature for it so i add the armature but blender wont mirror the weight paint, my model is for SURE symmetrical and the armature too, but like i sayd blender wont mirror the weight paint… better NOT ALL.

All bones have flipped names (name.L and name.R)
and i dont want to mirror all single vertex groups…

any tip for it?

It’s a little hard to understand your exact situation, but I’ll try to answer.

As far as I know, I’m afraid you’re going to have to mirror the vertex groups. This can be simpler than it sounds, especially if you’ve already got an armature with properly named mirrored bones, because if the properly named bones exist on the armature already, all you really have to do is reparent the mesh to the armature with empty groups. It sounds like you’ve made the bones but you don’t have the mirrored vertex groups, which you need for mirrored weight painting since vertex groups are what holds the weight information in Blender. Reparenting the mesh solves this because the mirrored vertex groups should be made automatically when you reparent the mesh to the armature.

If you make a backup of the model before reparenting it to the armature and then transfer weights between the backup and the reparented mesh, you should be able to preserve your current weights while still generating the mirrored vertex groups.

I have parent the armature to the model, and have for both sides the vertex groups (arm.L arm.R) but if i weight paint with mirrored x axes blender wont accept it and wont mirror it i just paint on one half not both. i tryd it with empty groups but i have the same problem, i tryd it with an NEW MODEL but there is the same problem.