This is an add-on for Blender 2.79.
It's a modal tool that lets you tweak the weights of selected vertices by dragging the mouse up and down.
It's useful for blocking and polishing vertex weights for skinning (armatures) and others uses (hair density, physics goals, modifier influences etc.).
- Select some vertices in Weight Paint or Edit modes.
- Activate it with Weights > Adjust Vertex Weights (in Weight Paint mode) or from a hotkey that you set up (read below) or by pressing space and searching for it by name ("Adjust Vertex Weights").
- Move the mouse up and down to offset the weights of selected vertices. If they're skinned you'll see them moving around as their weights are readjusted. Their weights from locked groups will stay as they are.
- Hold Shift for finer changes, press Enter to accept the changes or press Esc to cancel.
- Pose your armature to find out where your skinning needs work.
- Lock all of your vertex groups (to avoid surprises later). Then unlock just the ones that affect the region that you want to work on.
- Use weight painting brushes and this tool and the other weight tools to improve the deformation on that region.
- This tool has an option called Normalise Weights, it's best to keep this on when skinning with armatures.
- Protect Non-Deform Groups: when this is on, the weights from vertex groups that aren't used by Armature bones -- like for hair density and modifier influences etc. -- will not be normalised together with armature bone groups, they will be ignored. (Default: on)
Download the file "adjust_vertex_weights.py" after purchase. Choose "Install from File" from the File > User Preferences > Add-ons window on Blender and search for that file. Once installed, enable the checkbox on the add-on info box to enable it (and expand that box to see to addon preferences).
You can manually add a hotkey to this tool by going to the File > User Preferences > Input window and adding a new entry for operator "paint.adjust_vertex_weights" in the 3D View > Weight Paint category (similar to this).
You can add it to the 3D View > 3D View (Global) category instead if you want it to be accessible from both the Weight Paint and Edit modes.
You can also assign that operator to pie menus and custom panels.
Save your User Preferences after all these changes so they are remembered the next time you run Blender.
To delete this add-on find it in the Paint or User categories of your User Preferences > Add-ons window, expand its info box and press the "Remove" button.
Thank you for your interest!
For questions, bug reports or refunds: