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Vellum 101 - Pills (Rigid Bodies & Grains)

Someone (sorry, my poor brain can't remember exactly who) asked if it'd be possible to combine bullet dynamics and Vellum. While we so far only found unsatisfactory solutions for this problem, there is another way of simulating basic rigid bodies in Vellum.

In this tutorial we'll set up a workaround rigid body solution in Vellum and have it interact with grains.

Vellum 101 - Pills (Rigid Bodies & Grains)

Comments

Me too I want to know how to assign 2 colors to the grains.I tried following the file provided using Mantra but I can only get one color.

Dana Ismail

Hi Hussain, for the differently colored grains just set a point color v@Cd on your points before wiring them into a Vellum configure grains node. And yes, that's the reason (well, one of them) why grains are so fast: the only way to space them apart is to increase their radius using @pscale. Cheers, Mo

Entagma

Hi Mo! I had 2 questions please: 1- Im a bit unsure of how you made the grains into 2 colors. 2- For the VellumConstraintGraints, is there a way to space the grains out, at the moment it seems like the options can only scale them up/down? Thanks a lot!

Hussain Almossawi

hey. how'd you do that with attrib transfer? thanks!

@butterflysDust

Hi Ana, if you open up pills_falling_05.hip in the provided ZIP and dive into the pillsim geo node, you'll se how materials are assigned to different groups when you have a look at the material1 SOP. :) Cheers, Mo

Entagma

hey! I'm sorry; but how do I add material to the transparent group/different groups in houdini? Dunno much about materials/rendering with houdini/mantra. Thanks a ton!

@butterflysDust

Thanks Mo! Anyway here is what I was able to come up with after messing around in after effects. https://vimeo.com/342369133 . Tiny bit of MOPs in there too ;)

Thomas Roohan

I'm usually object merging separate parts of my sims into separate geos for shading too, so to me this sounds like the way to do it, but I might be wrong there :) cheers, Mo

Entagma

This was a great exercise thank you. I've combined some elements of the previous lessons to have the pill hit the ground and split open spilling the grains. Hope to have a render soon. Which would be my next question. I have a render setup where I'm merging the geo from the grain sim into seperate geo nodes in the scene. Not sure if this the best way to apply materials or if all materials could be done in vellum setup?

Thomas Roohan

actually I have solved this with attribute transfer . thanks anyway.

Amin Sadeghy

i mean for example in one pill grains to be red and the other pill blue ...

Amin Sadeghy

Hi Mo, I want to make the grains in each pill a different colour but I can’t for some reason. Can you please help? thanks great tutorials.

Amin Sadeghy

use particles? @orient

tim hart

Awesome Tutorial! Thank you thank you thank you. I have a question, Is there any way for Vellum grains to provide the orientation of the grains? Trying to instance geometry that looks like its rotating realistically. I assume I have to use the bullet based grain solver if I want orientation (But then I can't play with the vellum magic :( ) I have tried everything with no luck.

Bruno Canales

to visualize the grain bits without blasts, you can add a point wrangle and set @Alpha to 0.5.

jeremy jozwik

Loving these vellum tutorials! Thanks so much

Luis Román


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