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View Full Version : Cloth and ik not good bed fellows?

THE CORE
06-20-2002, 01:31 AM
Does any body out there know what the deal is with ik solvers messing up cloth simulations?

I have a cloth kilt on a low poly version of my character
which was working fine until I wrapped it to the main setup.
I searched for hours trying to work out what was causing the problem before finding a single post on highend3d from some one who seemed to describe the same problem and mentioned that the problem disappeared when they disabled the ik solvers.

of all the things it could be I had never considered the ik!
after doing a few tests I found that different types of ik solvers had their own destructive effects on my cloth.
single chain and spline solvers messed up the
cloth mesh constraints and RpSolvers messed up the cloth Collision, making it look offset!

the highend post also mentioned that this did not happen if the cloth was created before the ik and this proved to be true.
but due to the near completion and complexity of my character rebuilding is not an option.

I can kinda understand the history dependency of the situation but surely there is a work around I am not seeing as no production pipeline could accommodate something like this.

Please help it's driving me nuts!
:insane:
magicjeremy
06-20-2002, 02:53 AM
Core,

You didn't really say what the exact problem was, so I'm assuming it's a collision thing

I had a polycharacter rigid bound with a lattice, full rig and everything, but using the geometry inside the bind for collisons crashed the app every time. I ended up duping out the bind geometry and creating "live" blend shapes from the bound geometry. I then took those and used them as the collision objects. It might be a little sloppy, but it works. I also found that the collision setups are really dependent on creation order, hierarchy, and object history.

my magical formula:
1. make the Live blend shape (at scene level)

2. set collisions

3. drop back into hierarchy

simulate, bake and render


I hadn't heard about the ik bugging cloth out, but my rig's got ik out the ass and this worked for me.
THE CORE
06-20-2002, 04:05 AM
yeah sorry about the long winded non question.

Yeah its pretty much that the collision and constraint mess up when I have the ik enabled.

the only answer I seem to be able to get to this is - history order.

wahhh???

but thanks for the work around suggestion man!
its similar to what I had planned in event of a non answer

using the bakeCloth script on the wrapped collision mesh
and then solving on that

work arounds gotta love em!
magicjeremy
06-20-2002, 05:20 AM
cool.


sometimes it seems like everything is a workaround
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