Deform mesh along normal vector with Geometry nodes

Support Modeling
1

Hey guys,
I’m trying to setup a shot sculpt option with Geometry nodes. I also did a proposal on right click select:

A first rudimentary setup is working just fine, apart from one major thing, I can’t figure out. My deformation happens in object space, however the alembic cache doesn’t rotate in object level, but mesh data level. Is there a way in geo nodes, how I can transfer the deformation from object space down to let’s say vertex normal or something ?
Any help would be highly appreciated.

Here is my current blend file:
shotSculpt_001.blend (1.3 MB)
sphere.abc (2.9 MB)

I created a bulge on the sphere on frame 20, however when the sphere keeps rotating this deformation doesn’t stick with it.

Thank you very much for any help

2

Hey,
After playing and trying a bit more, I think I’m getting warmer. The deformation now stays in place. However the deformation does not 100% align with the corrective sculpt. I assume the vertices are being transformed along there normal Z towards the new vertex position. Probably I’ll have to rotate the normal to line up with the new position, and then push it out. Anyone any idea how I could achieve this, or maybe I’m completely on the wrong track.
Here the current blend file and the used abc within:
shotSculpt_002.blend (1.7 MB)

monkey.abc (2.9 MB)

Cheers,
Stefan

3

nobody willing to help me out there a little ? I can’t find the solution

4

I think you will find help faster in main Geometry Nodes thread here on forum.
Lots of people hanging there.

5

thanks mate, very much appreciated, I’ll try there

6

This would work only if you are modifying the mesh per frame and switching them quickly per frame, achieving transitions (animating the shapes on top of the cache) is going to be touch, because the SetPosition node overtakes the actual positions of the underlying cache positions. The offsetting does not seem to work.

I just tried it with another method, and like I said it could work if your modifications are per frame instead of general shapes that are meant to be morphed on top of the cache playback.

7

Hi kkar,
thank you very much for your reply. I want to show an use case example of what I’m trying to achieve:

I’m not really aiming to replace the geo as such, just to fix existing deformations. Right now the only way I can think of is with geo nodes, since I can have it after the mesh sequence in the hierarchy and create specific deformation deltas, which can be added on top of the existing vertex positions.

As you can see, it is kinda working, and you can also layer more fixes and animated them in and out (this example is based on the setup I posted 4 posts up).

My only problem right now is, that I can’t get the fix spot on. I am including the vertex normals of the reference mesh as well the animated alembic, so the fix stays in place and is not in object space. However the vertices are only being push out towards their normal direction. I’m trying to find a solution to get them to the exact wanted position, and still stick to the underlaying deformed geometry from the alembic.