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View Full Version : Serious Cloth/collison issue!



bluemars
05-18-2007, 09:12 PM
Hey guys, i'm running into some serious issue with the CLothFX/collision dynamics, i have been searching for tutorials and read the manuals but it doesn't explain why the cloth in my scene keep stretching downward, i set a fix point for the top of the cloth to prevent it from falling down, but the gravity keep on pulling the rest of the cloth downward,! i have tried to set the strech limit of the cloth to 0% but it doesn't seem to work, does anyone know how to fix that? if you want to check out my scene file, i'm more than happy to send it to you guys! thanks!

Surrealist.
05-19-2007, 02:26 AM
Yeah upload the scene file.

Do you have Dan Ablan's LW 8 book? He has a dress simulation tutorial. It sounds like for what you are trying you have missed something simple.

serge
05-19-2007, 05:29 AM
ClothFX can be quite tricky. Things might not work as you'd expect. Stretch Limit is one of those things. A stretch limit of 0% doesn't work. Try values of 0.1% or even lower to prevent the polygons from stretching.

Also, add some "Hold Structure", this will try to keep your object in it's original shape. "Sub Structure" can also be useful. It creates what you'd expect: a sub structure (extra geometry) to keep your polygons from collapsing on eachother.
With Hold Structure and Sub Structure, don't be afraid to put high values like 1000 or 10000. Of course, these values depend a lot on other values like "weight" and "gravity".

When you're testing be sure to check the wireframe of the object to get a better understanding of what the different parameters do.

bluemars
05-19-2007, 06:38 AM
Thanks Serge for that helpful tips, yeah it fixed my problem,!!! and i will check out that book surrealist!

anyway, i got another question, this time is relating to the keyframe timeline, when i clicked on the calculation for the clothfx, it starts calculating from frame 0 to 3000, and that's taking insane amount of time for it to finish, is there a function in lightwave that allows the cloth calculation start from a certain keyframe? like maybe starts from Keyframe 600 and up?

Dodgy
05-19-2007, 07:31 AM
Set your layout timeline range to 300-whatever, as fx only calculate for the timeline range. (not the render range or the make preview range to make it clear )

bluemars
05-19-2007, 07:56 AM
yeah, i have just figured that out, thanks!!!

But now for some strange reason the cloth layer won't/doesn't interact with my model, like it just stays there and do nothing when i clicked on the calcualtion button, but when i disable the cloth FX, the cloth layer moves along with my model but the fabric doesn't move(since clothFX is off), I'm so confused right now! like on problem after another, Dodgy, is it ok if i send you my file so you can have a look?

Dodgy
05-19-2007, 08:23 AM
Okay sure :)

bluemars
05-19-2007, 08:32 AM
i HAve just sent you my file,!!

bluemars
05-19-2007, 08:33 AM
and thanks!