Vellum 101 – pt. 38: Differential Edge Growth by Christopher Kopic 21.10.2021 comments 15 Part of: Vellum 101 Vellum 101 Differential, flower, growth, organic, Vellum To view this content, you must be a member of Entagma's Patreon at $29 or more Unlock with Patreon
Ha! This is great! I was just working on something like this. Perfect timing! I was trying to do the remesh in the same network stream as the vellum solve. Thanks for showing how to split up the data into multiple streams.
One thing I added was to subdivide the edge more with “adaptive” remesh. Just reverse the “growth” attribute with a min of 0.1 to “targetmeshsize” and then pipe that in to an adaptive remesh. Ends up giving you much more resolution on the edges where you need it. 🙂
Wish I could post images.
Hey Scott, yes, this technique works quite fine! Especially if you only want to grow your geo up to a specific point and no further. You can add all your edge detail before simming and don’t have to worry about remeshing mid sim!
… when you attribute transfer in sopsolver1 there is no ‘force’ attribute to transfer as far as I can see — am I missing something? Let me know – C
Hey Chris, this is more or less just for completionists sake. The setup I built in the tutorial has no force attrib since no external force is acting on the object. If you’re adding for example a gravity force to the sim, you get a force attrib as well.
yes — would love to know how to run the solver “lightly” without the jumps…
Yes! I would love to see a follow up with the adaptive subdivision. Bring on the vex!
When I’m creating the vellumobject inside of the DOPNet the defualt path isn’t set to the input 1 and input 2. I’m in 19.0.455 if that has an impact. Is that some configuration that I need to change? Also I’m curious why u have to type in `opinputpath(“..”, 0)` with the apostrophes, looking in the Houdini documentation I can’t see any references to this https://www.sidefx.com/docs/houdini/expressions/opinputpath.html
Just confirmed that these presets are indeed missing in 19.0.455. Very odd choice by sidefx…
In any case, the scene files are still working though, so if you’re having trouble, you can just copy this expression from there.
The apostrophes are actually backticks and it’s the houdini way of saying “I want to write an expression inside a string field.” It’s used here not because of the expression itself, but because of the type of parameter field it’s written in.
Hi. Thanks for your insight.
I’m looking foward to make an object
1) start from zero 2) and then scaling to one 3) and edge grow.
I was looking through ‘pin to target’ vellum but still can’t find how to..
Your help would be highly appreciated!
I would be very intrested in the adaptive subdivision with VEX, hope you make it ^^
Good News! I did! 😉
How would you adapt this to newer SOP based workflows?
Hey! I think parts of this setup (like the enable solver) are only available in dops. So unfortunatley no SOP-only version for this setup.
If you can show how to do differential growth in soft bodies I would appreciate it
Vellum Ballon softbodies should work without changing anything but the vellum constraint nodes (both on sop level and inside the solver) in this setup and the follow-up setup (pt. 39). Vellum Strut and Tet softbodies might work as well, but I havent’t tested them.