Strange artefacts on RBD Material Fracture Detail

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Joined: 9月 2024
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Hello All.

I am trying to recreate a VFX shot and I have been running into an issue with trying to create higher poly version of an object guided by a guide sim.

Whenever I added any detail, be it Edge Detail, Interior Detail or Chipping, I get these strange artifacts along my geo, in a range of severity. The one pictured is the best I could reduce it to, often times the artifacts would be so bad they would remove entire pieces of my fracture.

No matter what I do, changing the seed, reducing the detail size or element size, detriangulating and such, all of it has been to no avail and I have been ripping my hair out trying to figure out how to fix this.

Could there be something I could do about this?

Attachments:
artefact01.png (2.0 MB)
artefact02.png (2.0 MB)

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Joined: 2月 2008
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Can you share the hipfile here? Otherwise, file a bug and submit the file there and I can take a look at it.
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Joined: 8月 2021
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I also find fracturing with this node unstable and slow. My preferred method is to use voronoi fracture approach.
Check the screenshot for the setup but basically
1. Put a rest node at the very top of your clean mesh (set mode to "store rest"). Then displace your mesh using noise. attrib vop with turb noise added to P works, or just use a mountain node, your choice. Plug that noised mesh into the first input of the voronoi fracture.
2. For the second input, scatter some points. You can use isooffset + scatter combo or manually place some spheres to concentrate points where you want denser pieces. Logic is just to fracture the mesh while it's warped with noises.
3. Then drop an attribute wrangle and type
v@P = v@rest;
That brings shape of the mesh back but keeps the deformed edges.

Take that geo and run it through convex decomposition or a vdbfrompolygons + vdbtospheres combo to make your low poly proxy stream for the actual sim. Then at the very bottom, use transform pieces (matching by @name) to move high res pieces.

If you can afford it I'd ditch the rbd interior detailing and use normal/displacement/bump maps in texturing phase. Otherwise you can try to take the "inside" group that voronoifracture provides, isolate outside edge aka unshared edges and displace everything but the unshared edges (so you can keep the fractured mesh's integrity).

Attachments:
voronoifracture.png (48.4 KB)

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