When editing or painting weights of smooth skin objects, you sometimes want to ensure that the weights of certain objects won’t change. For example, if you’ve perfected the weighting of a particular object, you don't want the weights to change due to the Normalize Weights mode you have enabled
When locked, Maya keeps those weights at their current values as you modify the weights of other influence objects. You can still modify the weights for those objects by directly editing influence weights in the Component Editor.
To lock weights using the Paint Skin Weights Tool
next to an influence.
-click and select
Lock Selected.
to invert the selection, then
-click and select
Lock Selected.
To lock weights in the Component Editor
This tab displays each influence affecting the selected vertices in a column layout.
When you set the Hold cell to 'on', the influence also displays with a lock icon in the Paint Skin Weights Tool.