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Cloth: Self-collison Doesn't Seem To Work
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Cloth: Self-collison Doesn't Seem To Work // New Users
Post by johnhoward // Aug 5, 2008, 1:14pm
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johnhoward
Total Posts: 231
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I am starting with a two-sided plane (as described in Jack Edward's tutorial) and letting it drop onto a hoop.
I have self-collision on, but the fabric passes right through itself. It appears to behave the same whether self-collision is on or not. Is there another control I don't know about?
Thanks for any clues. |
Post by Jack Edwards // Aug 5, 2008, 11:15pm
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Jack Edwards
Total Posts: 4062
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hmm... I might be wrong to use a 2-sided plane. I did that for visibility reasons. This could definitely use some testing though. :confused:
You could also try increasing the cloth thickness setting. |
Post by brotherx // Aug 6, 2008, 1:09am
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brotherx
Total Posts: 538
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When I did some experimenting with the cloth I actually used a very thin (around 0.01ish) box.
see results |
Post by johnhoward // Aug 6, 2008, 6:26am
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johnhoward
Total Posts: 231
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Thanks Jack and Brotherx,
I find that nothing works so far. If I use a 1-sided plane, then holes appear where the self-collisions occur. Also, when draping cloth, it is often the case that we see both sides of the cloth, so a 2-sided plane makes sense. A plane vs. a box also means a lot less physics calculations.
When I use a box (I tried both .01 and .001), self-collision still does not work, and the thin box edges become stretched and thus become thick box edges. I even made the "stretching" parameter 0 so the edges could not stretch, but they did anyway.
It seems the best answer in theory would be to get self-collision working and then use a 2-sided plane. |
Post by Jack Edwards // Aug 7, 2008, 12:55am
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Jack Edwards
Total Posts: 4062
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Could be an issue with normals as well. Have you tried changing to the "Special" aspect of the PhysCloth panel and checking the "Update Normals" box? |
Post by johnhoward // Aug 7, 2008, 4:15am
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johnhoward
Total Posts: 231
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Yes, it has been checked, by default I guess. I have experimented with unchecking it and rechecking it and that seems to readjust how light hits the two sides of the cloth (this can also be done by using "Auto Facet Normals" button), but has no effect on the self-collison issue, as far as I can tell.
It strikes me as very odd that "self-collision" is an option with cloth (why would you want cloth ever to pass through itself?), even odder that the default is off, and disappointing that it doesn't seem to work under any circumstances. |
Post by Jack Edwards // Aug 7, 2008, 10:02am
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Jack Edwards
Total Posts: 4062
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John, can you post a scene with the problem so the devs can take a look at that? |
Post by splinters // Aug 7, 2008, 10:54am
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splinters
Total Posts: 4148
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Gotta admit that I had a few glitches with cloth myself so I just left it and moved on. I will see if I can recreate them...:o |
Post by johnhoward // Aug 7, 2008, 11:18am
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johnhoward
Total Posts: 231
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Jack,
Here it is. In order to get in under the 2MB file limit, I had to eliminate the texture, but otherwise it is the same scene. The cloth is a double-sided plane and self-collision is checked.
If you let the cloth drop for about 12 seconds (using the PhysEngine "current Time" counter) you should get something pretty close to these JPGs (one with texture, one without texture).
I'd be interested in knowing if it performs the same on your machine. |
Post by frootee // Aug 8, 2008, 4:28am
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frootee
Total Posts: 2667
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just a quick tip john et al...
you can upload zipped (*.zip) and RAR (*.rar) files up to 20 MB in size.
So you can zip or rar your file which is greater than 2 MB in size and still upload it.
Froo |
Post by johnhoward // Aug 8, 2008, 6:10am
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johnhoward
Total Posts: 231
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Thanks Frootee - good tip. |
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