Hello,

I'm trying to animate a hanging sign and I can't get the chain links to stick together. I have the top link attached with a pin constraint to a ceiling and that is working. The other chains just fall with gravity, which I've tried turning down to -0.01 and the same result. I have tried uping the max substeps to 10 as well as uped the divisions to 60x60x60. If I look at the links in “show collision geometry” mode the links look like they have enough divisions to create the same shape as the geometry. I have made sure that the links are not touching (or their collision geo) at the beginning of the simulation. I'm using ray intersect collision mode.

Any suggestions?

thanks in advance

did you check the affector relationship in the merge modes in your autodopnetwork? are the links not set up to collide with each other?

Are these the correct settings?

Affector Relationship: Mutual
Relationship: Collide Relationship

can you please post a hipfile?

I'm a total noob to houdini (3rd month), any help is really appreciated.

can you post an image of what you are trying to do.

2 things you can do,
set RBD object and clone it on the Dopnetwork context;
clone it on object context, and more edges. (so the chain link dont pass each other)

other thing you might want to try is this, model the chain. i am assuming a straight line. then model a curve with the shape of the chain. and use a wire simulation, and just pin the first point of the curve. this waythe simulation will a lot faster since doesnt have to calculate collisions (with each chain link with each other)

and then just deform the chain with the curve.

My goal was to use dynamics to “model” the animation in a realistic fashion, as opposed to animating it by hand. I tried animating it by hand and it looked very amateur, so I'm trying to make it look realistic by doing a dynamics simulation.

I wanted the sign to move with a wind force that I was also going to use to make some dust clouds as well. I figured that if I used the same force node, then the simulation would look more realistic. So the wire simulation will probably work, I just thought that houdini could handle chain links (maybe in 5 more years). My only problem with the wire simulation is that I lose out on inter chain rotations, like when there is slack in the chain and the links will twist in different directions.

The ultimate goal, which may be unachievable, was to have the sign move with some wind and then simulate an earthquake (shaking) and have the sign fly off and hit a propane tank that is nearby. I had to delete it from the scene in order to post, but that part I think would be easy to do. The problem I don't know how to fix, is how to get realistic(ish) looking chain links.

thanks

hey James,

sorry for the late response,
but have a look at the hipfile that I dug out of my computer,
I think it was posted a long time ago on odforce!
that should help you - and of course it's possible with Houdini to do such tasks

all the best,

Manuel