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View Full Version : Cloth FX, and Collision and different surface properties.



Neilus
07-05-2004, 07:01 AM
I'm having difficulty replicating the Jump_Dress cloth motion and collision with the new Cloth FX. This has been discussed elsewhere but wasn't really answered, in Protons example he uses 2 different cloth surfaces, how do I do this in Cloth FX?

And on a general note the Collision seems nowhere near as accurate as what was achievable using Motion Designer?

Lynx3d
07-05-2004, 08:45 AM
Well i messed a lot with it, and i'm 99% sure that the jump_dress scene was not calculated with LW8 dynamics, at least not with those meshes, because it is simply impossible.

Collision IMHO really sucks, LW only checks if a point of the cloth hits a poly of the collision object, but a spiky object may go right through the middle of a cloth polygon. That's exactly what happens with the knees of the animated girl there all the time...
I haven't explicitly tried, but i also had the impression that even in LW6 MotionDesigner did a better job there!

If you go back to Modeler and Bandsaw the skirt like an idiot it suddenly works...
Also in that scene, the skirt is actually animated by bones, which does not seem to work well with the calculation either...had to change that.

Besides that, make sure there is (almost) no bound (or it will just shake harder with every collision and go nuts), a little hold structure and viscosity (i used 150 and 6), and don't use "object advanced" on the collision object, i don't know what it is supposed to do, but it certainly breaks some stability rules of mathematics, my cloth just went crazy.
I think whoever wrote those dynamics should read a good book and rethink its algorithms...

After half of my hair turned grey the best i could come up with was this:
http://lynx.aspect-design.de/stuff/jump_skirt.avi

I am certainly not impressed with LW8 clothFX...

Neilus
07-05-2004, 11:15 AM
The scene was made via MB in 7.5, the motion *.mdd file has been loaded onto the skirt via Cloth FX. I'm 99% sure to,

You can load up the Motion Designer Controller and re-activate it in there.

Unfortunately these values don't seem to have any bearing on the new dynamics, Cloth FX or Collision. And Motion Designer seems to give better results, so why bother with dynamics in 8?

Did you disable the bones deforming the skirt then?

I'll try cutting up the skirt more to refine the geometry.

Cheers for your help.

Hervé
07-31-2004, 12:29 AM
Man, that cloth FX really suk.... it does not work as advertised at ALL.... I've spent one full day trying to put a towel on the back of a chair... should have been very simple... (and I am sure in Maya or XSI, it would have taken 5 minutes) one full day and No results.... (sure LW is not expensive, but in the long run, you pay anyway...) so I am thinking about workflow in LW... and I know a few of U are trying also...

well, very bad.... and I know there is no solution other than

1) 10 cm Gap between the collision object and the towel (no go)

2) I've subdivided the 2 objects as much as I could.... no luck either, just slower to fail....!!

So we paid for ClothFX in 8, but it was a rip off....:mad: :(

Hervé
07-31-2004, 04:37 AM
.... well.... just not possible... prove me the opposite if ou dare....

I am just going to model it in the position I want It'll go mucho faster....

NT badly failed with cloth... :D

ColinCohen
07-31-2004, 08:28 AM
Originally posted by Lynx3d
I think whoever wrote those dynamics should read a good book and rethink its algorithms...

I would recommend Cloth Modeling and Animation by House & Breen.