How to mirror copy existing vertex weights So far I only find option to mirror the existing weights, but didn't find a way to mirror + copy it, I mean, I want to create symmetrical weights on the other side, but I also want to keep the original, both sides should be in the same group.

For example:
Copy your vertex group
Mirror your vertex group


Now you just have to merge them togerher. Do it with script if you wanna automatize it or by hand:


How to merge vertex groups?