I've been working on a simulation (you can read about it here [www.sidefx.com] if you're interested) and I'm struggling to find the right balance of various parameters to achieve the desired effect. Is there a logic for how to balance, for example, stiffness and damping, especially across two different constraints? I'm sure there's always at least a little guesswork, but right now guesswork is all I have, and I have to believe there's a better way.

Now you know why all the VFX guys are overworked...

The general rule is to change a parameter quite a lot to ensure it's the parameter you like to change, and then "binary search" on it. But I believe you already know that.

I'm not sure what you mean by "binary search".

gordig
I'm not sure what you mean by "binary search".

The binary search mentioned above is a way of solving a problem where you don't know the end result, you start dividing the original range in half and search for the parameter value in each part recursively until you find it. For example your range of values can be from 0 to 100 and after dividing it in half you can search for the desired parameter value either from 0..50 or 50..100 and keep dividing each range again until you are satisfied with the final result.

Ah, thanks. I usually just shift decimal points until I'm in the neighborhood.

Binary search, or perhaps rather the bisection method, is one of those algorithms taught at the IT university which one might think is limited only to IT, but then he quickly realizes that it makes life easier outside the computer world. It's especially helpful when your grandmother asks you to hang her window curtains.

Kind of a poor attempt of a joke from my side, but those who did this activity (hanging curtains with millions of rusty clothespins) will know what I'm talking about.

That's one thing wedging can help with. Set up Tops and wedge the values so you can see all the different results

Man, I haven't even looked at TOPs yet.

Since solvers in Houdini are not 100% physical its difficult to rely on specific values unfortunately, even for solvers like Bullet

It definitely helps to understand what each solver is doing, whether it compensates for scale or mass or completely ignores those properties etc ..

Also with vellum things like substeps and iterations play role when tweaking stiffness for example since higher stiffness may need more iterations to converge and effective stiffness also scales with mass, etc ..

Then, after you understand what each solver does, I'd say it's mostly about building intuition about each solver's behavior, the more you use it the more you will understand how it behaves and be able to tweak the right settings quickly