Weight Painting
Weight painting is an alternate technique for assigning vertices to vertex groups. The user can "paint" weights onto the model and see the results in real-time. This makes smooth joints easier to achieve.
Activating
To activate weight-painting mode, select a mesh with vertex groups and click on the weight paint icon.
The active mesh will be displayed in weight-color mode. In this mode dark blue represents areas with no weight from the current group and red represent areas with full weight.
Only one group can be visualized at a time. Changing the active vertex group in the edit buttons will change the weight painting display.