Hi guys,

So I have a wire sim that is taking an incoming velocity field through a sop solver in a point wrangle, but I also want to add a simple secondary wind force to the sim. I wanted to know if I could avoid having to make another custom velocity field or there were any other techniques used instead.

Its not a huge deal to make another, but yeah just curious. From what I could find it seems that I do need to make a custom force; the POP wind wasn't accepted by the wire solver; and the Wind Force node does not work as expected.

Let me know if you got an idea

Thanks guys

You could try using Vellum instead. Then you can dive inside the solver and stack up pop forces.

Hi Enivob

I was originally going for a vellum work flow and I was using it until I realized the complexity of the tree I have. The branches are curvy and I can't reduce the point count on each branch enough to get it to a point where they would be stiff in the vellum solver (even with high substeps and constraint iterations). The wire solver has worked better in that regard, though I wish it was vellum that worked better because of it functionality with pop forces.

Thank you for the suggestion though, if I have less complex trees in the future I would 100% use vellum.

you can use POP Solver, uncheck everything except for Use Implicit Drag, Integrate Velocity and Use Mass
then into pre solve connect your pop forces, like POP Wind, etc and to post Solve connect Wire Solver

then you will have wire solver and still be able to use POP nodes

tamte
you can use POP Solver, uncheck everything except for Use Implicit Drag, Integrate Velocity and Use Mass
then into pre solve connect your pop forces, like POP Wind, etc and to post Solve connect Wire Solver

then you will have wire solver and still be able to use POP nodes

@tamte, what love to know what your chain of thought was here to figure out that you can plug the wire solver into the pop solver. Was this from experimentation or what is the logic you used to figure this out? Thanks in advance.

miccetro
@tamte, what love to know what your chain of thought was here to figure out that you can plug the wire solver into the pop solver. Was this from experimentation or what is the logic you used to figure this out?

there's definitely logic involved, I don't like using setups that wouldn't make clear sense
it's partially experience with how DOPs work and then knowledge of inner working of POP Solver (since it's hda that you can look inside) which makes such connection less mystical

if you dive into POP Solver you can see what it does, it's just a bunch of microsolvers doing specific operations, so the only interesting part here are nodes that integrate v@v from force and wind specific attributes, which luckily the mentioned checkboxes allow you to do
so in that configuration POP Solver is just solving for new v@v

then traditionally you'd combine solvers using Multi Solver DOP
so you'd just append Multi Solver to your object and connect both POP Solver (with all POP forces connected to it's presolve)
and Wire solver to the Multisolver

however since POP Solver is already internally a multisolver and also has a post-solve input which is executed after v@v is integrated you can just utilize that instead and connect wire solver there directly, eliminating the need of another Multisolver
it will also make it substepped by POP Solver's settings since it's internally connected to Gas Substep, which whether desired or not is good to keep in mind

Hey guys, this thread literally made my day. It solved my issue of trying to make a haircut really stiff but it was impossible. This Wire solver is great.

Would it be possible to combine the vellum solver and the wire solver with a multi solver? I tried as per the example with the Pop solver, but it doesn't work.

EDIT: but maybe what I am asking for is nonsense as vellum hair and wire solver would be kind of conflicting with each other I suppose(they are kind of doing the same thing). I don't know Houdini enough to understand the underlying specificities of each solver.
What I would like is the @kangular attribute from the wire solver and use it with my vellum solver.