Is there a modifier that will add my current geometry to a vertex group?

Question

Imagine you have an object with some boolean operations in the modifier stack. On top of that you have a remesh modifier to melt everything properly.

now what I am trying to do next is using a vertexWeightProximity Modifier to create vertex weights based on an empty object. However this vertexWeightProximity Modifier does need a predefined vertex group to work with. When adding a vertexGroup to the source object, it does not take the newly generated geometry created by the remesh Modifier into account. That's why I am asking if there is any way to tell Blender at some point in my modifier stack to add the current state of vertices to a vertex group.

Fyi: applying my modifier stack after the remesh modifier is no option in this case because some of the boolean operations will be animated, thus the geometry will change with every frame.

Thanks in advance.

Answer 1

If you would do the boolean operation inside Geometry Nodes, you could transfer the resulting mesh into the vertex group. Then the Vertex Weight Proximity modifier would have access to it.

Here is an example how you could do it. I have one sphere as the base object which holds the Geometry Nodes and Vertex Weight Proximity modifiers. It also has a vertex group called "Group". Inside the GN nodetree I use Mesh Boolean set to difference to subtract another sphere object.

In the Group Output node I added an output and set it to Type: Float and Attribute Domain: Point and set the value to 1.

In the Geometry Nodes modifier under Output Attributes I click in the empty field next to the label "Output", there should come a dropdown menu with a list of attributes, I choose Point > Group.

Now I can select the vertex group "Group" in the Vertex Weight Proximity modifier. Then I used a cube as the Target Object moving back and forth to show it's working. The only problem is you still won't get the Remesh modifier to work with it, but maybe there are ways to manipulate the mesh in Geometry Nodes to get a helpful result as workaround. This is my setup:

And this is the resulting weight painting (sorry for the crappy quality):