One of the most exciting features that Houdini 17 introduces is Vellum: A new simulation framework based on XPBD. (Extended Postion Based Dynamics – In essence grains on steroids.) That means stable and fast simulation of (almost) everything softbody: Cloth, Wires and well – softbodies. In this quickstart series we’ll take you through the bare basics of how to get started using Vellum.
Congratulations to everyone at SideFX and thanks a lot for creating this / these awesome tools!
Without further ado here are the tutorials:
Thank you for sharing.
Great as usual. Thanks
Thanks for the link, i wasn’t able to make it works, 🙂
Thanks so much for posting about new features and for doing it in the middle of the week, at launch, instead of waiting for your next typical Monday post. I really appreciate the effort.
When you say “your slow machine” in Part 1, what do you refere to? Hopefully not the Building your own houdini workstation build 😉
Referring to my other, older i7 machine that’s used for tutorial recording here 🙂
Cheers,
Mo
Hey Mo,
Thanks for sharing.
I’d like to know why you chose to go freelance. Maybe you could share some business knowledge. Just to get a general idea what it’s like be a freelancer.
I’d love to see a conversation like the one you had with Manuel.
Cheers
What kind of simulation times are you seeing on these files? I have done a few tests on both Mac with external GPU/Vega64 and PCs with internal GPU. In general using the CPU is a lot faster than GPU and Nvidia HW at least twice as fast as AMD (Vega64 and GTX 970 have about same speed, while GTX 1080 is twice as fast as these). My testing is not conclusive at all but it would be interesting to here your experiences with Vellum/OpenCL.
In my case, opencl is not ussing at all the GPU despite of ussing last drivers and setting up the .env file
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How did you manage cloth collision bounciness using vellum !??
One question –
is Vellum supporting multi GPUs – and/or SLI?
thanks a lot.
Flo, how did you manage to use the opencl?
In my case, opencl is not ussing at all the GPU despite of ussing last drivers and setting up the .env file
Thanks
Does anybody know how to add pressure in the vellum balloon?
use the basic vellum balloon config, drop down a vellum solver. inside add a vellum constraint property. set the group to: @type=pressure then animate the rest length. lower values will deflate, higher values inflate.
Hi!
First, you have maybe the best houdini page, I love what you do.
That said, I need your help.
I need to simulate poles and cables breaking and interacting.
Should I use only bullet and different contraints or should I mix with wire solver or vellum?
Is it possible to mix RBD and Vellum in a single sim whit the both, poles and cables, braking and sharing forces?
Thanks you very much.
Thanks a lot for the introduction. Cool videos!
In my case not sure about the opengl working on my gpu. Can not track any load increase on it.
Anyway here is some result 😀
https://youtu.be/Q7J8NZgLBA0
Very cool, thanks. Quick question – why do the remesh instead of simply upping the polygons on the original mesh? Is there an advantage to random triangulation as opposed to quads which is what I thought cloth solvers liked?
I tried to exact same sim with the same poly counts on a quad mesh and on a remeshed mesh and got very different results on how the cloth behaved.. hoping you could shed some light on this. Thanks!!
Hi Isaac,
every simulation you’ll be running on a computer will involve some sort of discretization. Meanin instead of calculating an infinitely dense mesh, you’re stuck to calculate physics on a few points that make up your geometry. This of course results in errors, as not every atom of your mesh van be simulated. So a big part of CG sims is figuring out a configuration in which these errors don’t show up too much. When running simulations with a regular mesh you’re introducing very regular errors, which in some cases can be troublesome as the human eye picks up regular patterns very well. Also some calculations can become unstable as numerical errors can sometimes accumulate more easily when variables such as point distance or angle between points is eactly the same. Thus it can be a good technique to run the sim on irregular meshes. Which is what we’re doing with the remesh SOP 🙂 Again as always in CG – there are times when you wanna use irregular meshes vs. times when it’s perfectly fine to use regular meshes. Trial and error. The beauty 🙂
Cheers, Mo
Thanks for the thoughtful explanation Mo! Indeed the sim on the irregular mesh looked nicer than the quads. Just coming from Maya trying to run a sim on an irregular mesh like that would be just beyond a bad idea 🙂
Just started the full Vellum course btw. Cheers,
Excellent tutorial Moritz! Thank you.
I have one question. while doing the shooting pigs tutorial I decided to turn up the vellum solver substeps in order to get better collision evaluation. When I did this the point wrangle velocity values were not coming through and the pig heads would drop straight down. I was wondering if you had any idea why this might be happening ?
Cheers,
John
Hi John,
that is really strange. I just tried it myself and everything is working as expected here. Tried it on H17.0.416
Cheers,
Mo
Nice! The best source to learn Houdini on the web. Just a quick simple basic question, how do I make a dynamic object collide with the vellum cloth? It works simple on a static object but I can’t figure out how to make it work on dynamics. Example: a ball colliding on the goal keepers net. Thanks.
Jafet.
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