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Vellum Cloth Collision


Zigmund

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Hi everybody.

I have a cloth rack with hangers and clothes on it. The rack moves along the path. I simulated and cached the hangers moving with the rack. Then I modeled and draped the clothes on a static hanger and copied the draped clothes to each hanger to simulate the clothes on the moving hangers. I thought instead of using static deformed object it is better to use RBD fractured object (making it inactive) with point position, translating the transform of the hangers, so it would not load the collision geometry every frame. To help the vellum follow the animation of the hangers I also soft pinned with match animation those parts of clothes that "touch" the hangers. 

The problem is, after a couple of frames, the clothes start to penetrate the hangers. Increasing the substeps (tested with 10 and 20 substeps), collision passes, polish, post collision passes doesn't solve the problem.

VellumColIssue.thumb.png.6267b8bef001578b4bc9d94bad809ac6.png

So generally I have 2 questions, first is: which collision type is used in vellum simulations: Bullet or Volume?

And second: any thoughts on how can i solve my problem?

Loading hangers through static deformed objects also dramatically increases calculation time.. Or is it the only option for vellum?

Thanks in advance!

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44 minutes ago, Noobini said:

just works...

i still don't get ppl's attitude to wanting help but don't want to upload their files...f'kin annoying.

 

vu_shirt.hiplc

Hey, Noobini, no need to be rude. Here is the file. Freezed the draped cloth so no need to drape them again. Your case doesn't have RBD fractured object as a collision. I did it on purpose, so, as i said, by using the fractured object i can transfer the transformation, so no need to use deforming object.

 

test_lag_ClothRack_v1.hipnc

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5ed0ad24c3b13_RBDvellumtest.png.86101249165b1e8006163e3656366151.png

If you use vellum SOP solver, it has static deforming object in it, which works. Instead I used RBD objects set inactive. The idea is to transfer the transform in DOPs, so no need to load it every frame.. In case where I have many colliders, I used RBD fractured object to transfer the transform to each colliding object separately...

VellumRBDtest.hipnc

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you are using Volume based collisions in your rbdobject1, if you display Collision guide you'll see what's colliding against, you can either tweak the volume resolution or if you don't want that you can uncheck Use Volume Based Collision Detection

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Tweaking the resolution didn't help, but turning off Volume Based Collision Detection finally solved the issue. Thanks a lot guys!

Just a general question, why Vellum doesn't like volume based collision?

Edited by Zigmund
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