Maybe you are talking about this method but I don't know if there's another one. Let say you want to mirror the left arm group to the right.
If the right group already exists (because you've parented With Automatic Weight), delete it.
Select the left group and copy it.
Now mirror that copy.
Give it the correct name, i.e. with the correct suffix. This way ...
A smooth deformation of a bunch of vertices is always due to a balancing between 2 or more different weight assignements: if a vertex is weighted to a vertex group only, it will move with its relative bone rigidly and exactly, even if the weight is 0.00000001. Instead, if it has some weight relatively to two (or more) vertex groups, the movement is ...
You can erase with draw brush. Change the weight parameter.
0.0: Deep eraser
0.3: Shallow eraser
0.7: Shallow brush
1.0: Deep brush
Weight paint does not wet only vertex. Clicking on the vertex makes it dark.
Mirror side is not wet.
Weight values is recorded on the vertex data of the target mesh.
Vertex data is made only of the number of ...