Using geometry nodes, is it possible to transform vertices, that are in a specific vertex group? Let's say I create object primitive plane and I create a vertex group. I add one vertex of the plane into the group but leave the other 3.
Is it then possible to transform that one vertex in the group using geometry nodes?
It's possible and really really easy to do. You just need two nodes to make it happen
Demonstration:

Node Setup:

Note that test is the name of the vertex group. Also the vertex group should have weight of 1
(I am using blender 2.93)
To change material_index follow this node group:

Demonstration:

P.s. For it to work, U have to select the target faces(editmode)-&gt; right click-&gt; shade smooth them