how do i effect a single finger with gradient weight painting instead of the whole model

Question

im trying to give each bone on this model a manual weight paint. im using the gradient tool to give it a paint but that gives the whole model a paint instead of a specified area (like masking) making me have to manually remove all of the paint on the other fingers. is there a way i can make the gradient tool only effect a single finger?

Blend file : https://drive.google.com/file/d/1wRpmO1wKfbsdcmDQ6JxemHRVYY_-QJ9W/view?usp=sharing

Answer 1

You can use the Face selection masking or Vertex selection masking to do that. It is possible to do the selection in Weight Paint mode because you get the Select Tool there as well if you enable selection masking, but it is maybe even easier doing the selection in Edit Mode:

1. Select the faces or vertices you want to be affected by the Gradient Tool (sorry for this strange hand):

2. Go into Weight Paint mode and either enable Face selection masking or Vertex selection masking (you'll see the Select Tool appear then as well):

3. Now you can use the Gradient Tool and only the selected faces or vertices will be affected. Since you paint weight onto vertices, of course unselected faces connected to selected ones might show some weights, too, because they share vertices.