Skin Weights Copypaster

This extension adds basic copy\paste and set weight capabilities, common in other 3d editors but for some reason not in Blender:

• copy weights from one vertex to the selection
• set a precise weight for a certain vertex group
• select an edge loop in Weight Paint mode

The Paste Weights operator has two options:

• Clear existing weights removes existing vertex groups for target vertices before the pasting
• Normalize weights normalizes weights after pasting if the copied ones were not normalized

I didn't find any free extension that provides them, so I wrote it myself