Clothfx = I'm stumped

[Wopmay]

Hi.

I'm completely baffled. A simple question: Am I trying to do something LightWave can't do? Namely, cloth colliding with itself. I have the material set to collide with self and everything else. Seems like I've tried every setting and nothing prevents the cloth from passing through itself.

http://universalbinary.com/qt/CurTest06.mov

What am I missing?

Thanks,
W

[pnevai]

I recall reding somewhere that collision detection is detected only on the facing normal. So if your polygon is a simple flat object and not a object with actual front and back facing polygons then collision will not be dectected on the back side. It has to be a true double sided object and not just set as double sided etc.

[Rigel]

Other than the passing through itself problem, that looks fantastic.

By the way, you can upload videos to your posts as well.

[Wopmay]

Thanks. I'll give that a try.

The polys here are 2-sided. Naturally I've tried collision detection on front and back with no luck. You're saying that the collision settings refer to the object, not the poly?

You'd think they'd mention that in the manual. Guess I'll have to brush up on my mind reading skills.

W

[pnevai]

Actually the object has to have depth, I.E real polygons facing both front and back, not just a simple flat plane object that just has double sided enabled. It has to have both the front facing and back facing polygons modeled, with the poly normals facing the proper direction.

[Wopmay]

Other than the passing through itself problem, that looks fantastic.

By the way, you can upload videos to your posts as well.


Is uploading to the board preferred, better, faster or anything?

Yes, I'm impressed with the overall simulation. By the way, this animation uses Final Gather and Real Lens blur and the render times were a lot faster than I expected.

Thanks,
W

[BillS]

We prefer to have things uploaded here. That way the threads over time don't end up with a bunch of broken links when people straighten out there web space.

[Bells of Freedom]

I find dynamics, although fun and fascinating, to be a bit hard to troubleshoot, considering the multitude of settings that require many little tweaks. A couple screenshots of your Cloth Dynamics settings might help.

[Wopmay]

Hi, Bells.

I was going to post a new test and some screen shots but after working on it most of the weekend and a good part of today without ever getting the cloth to collide with itself in any significant way, I've all but given up.

The docs (what precious little there are on the subject) claim it's possible, but after searching around the internet for a tut or anything, I couldn't find a decent example of it. About all I found was people complaining about ClothFX self collision being little more than a fantasy.

Maybe it's me. Probably is.

If anybody knows where there's an example of LightWave cloth colliding with itself like this, I'd love to see it.

Cheers,
Woppy

[Wopmay]

In case the external link to the movie in the first post disappears, here's the file uploaded to the forum.

W

[Gordon Robb]

Wopmay: It looks great. I've done some messing with this for a short animation I did. I am almost certain that I got it to work without having actual depth to the object. I think it was something to do with a setting that sets the thikness? and also there are settings that set how complex the mesh is (dunno - don't have LW in front of me), but if you tell it to do more calculations per poly, I think it works.

I'll dig out my scene and or have a look at it later if you haven't got it sussed.

[Wopmay]

Hi, Gordon.

I take it you mean the "resolution" setting when you say "calculations per poly?" Maybe that's the key and I just haven't cranked the value up high enough. Or low enough? It's a bit difficult sometimes to figure out what Newtek means. I devine from the docs they mean a lower number is more accurate.

I have doubled and quadrupled the poly count. Maybe not enough but the calc time was going through the roof.

As for the mesh requiring actual thickness instead of two-sided polys, I tried that. No luck. The Newtek docs seem to indicate two-sided polys will work. Who knows?

In this particular animation, maybe the calculations are just too complicated for a desktop computer. It might work fine and dandy on this:

http://www.physorg.com/news102180615.html.

W

[McFilms]

You might check here (unless you already have): http://www.lightwiki.com/Introduction_to_ClothFX

Once I followed the tutorial by Dodgy, I was able to tweak setting listed there for another, unrelated project. If nothing else, it might touch on something you might have not thought of.

[Wopmay]

Thanks.

Yes, I've seen that tut. Just reviewed it last week, in fact. Very nice, except the problem I'm having is self collision, not collision with another object. Can't seem to find much of an example of it out there. Still looking. If anybody comes up with a solution, a cheat or an animation of it working (in LightWave), let us know.

Maybe I'll post the scene in case anybody else wants to try. Unfortunately, I've saved over the file that created the animation attached above. I'll see if I can get back to something close if anybody wants to give it a go. Maybe it should be a contest. Hmm...

Cheers,
W

[Gordon Robb]

wopmay, sorry for not getting back to you sooner.

This is what I came up with. Object doesn't have to have weight, it has to have definition.

Mess with the Bind setting in Collision, and make sure it has lots of polys. If it is SubD, then set it to a big number of subdivisions, if it is not, subdivide it in modeller.

there is some distortion here as it still needs to have higher number of polys.

File is DivX, let me know if you need it not to be.

[Wopmay]

Well, rats.

For some reason, the file won't play. All I get is a blank screen. I'm on a Mac.

I think I've been able to see AVIs before. Hmm. I assume it's me but I noticed earlier today I can't open any AVIs on this newfangled forum.

I'll get back to you.

Thanks. I'm anxious to see it.

W

[BillS]

I was reading about Blue Gene/P a few days ago. That would be scary fast!

[Gordon Robb]

NO problem. It'll be because it is DivX, here is a mov version its h.264

[Gordon Robb]

I was reading about Blue Gene/P a few days ago. That would be scary fast!

What's that?

Edit: Oh found it, why are we talking about it? :confused:

[Wopmay]

Thanks, Gordon.

I finally got the first file to work and now I see you've posted a MOV. Thanks so much for your trouble.

So. I'm encouraged to see that it actually will work. Very cool. I'm also discouraged when I think about the number of hours I've spent without even getting close.

Back to the drawing board, I guess.

I'll try your suggestions and see if I can figure it out. (Although, I thought that was what I was already doing. :confused: )

Thanks again.

:) W

[nikfaulkner]

thanks for the insites into possible problems, any chance of a scene file gordon :)