which attributes helps nCloth with those artifacts??

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Old 03 March 2013   #1
which attributes helps nCloth with those artifacts??

Hello,
I am trying to set up pants with nCloth. But I am getting the bad results you see in the image.
It looks like the pants are picking on each vertex of the body,so each vertex is bumping. I have been trying ti play with many properties to clean that, but I donŽt find the right one.
Any advice?
Thanks
Attached Images
File Type: jpg pants.jpg (53.6 KB, 29 views)
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rH
 
Old 03 March 2013   #2
I find a solution, but I thing it must be an easier way because my solution is too slow and more complicated.
The problem was that the rigid body didnŽt have a smooth mesh. So I did a copy of the mesh with 2 smooth divisions (and I deleted the useless faces, so I kept only the ones that conformed the legs). This copy will be the collider. Then I wrapped it to the original mesh that is skinned.

Doing that the nCloth looks fine because it is colliding with 2 smoothed division mesh. So my question is: isnŽt there an easier way? IsnŽt there a properties or something that tells to act the original mesh as if it was smoothed twice, without actually having to do a smoothed copy, and wrap it. Or isnŽt there any thing to make the cloth adapt better to the colliding mesh?
IŽll keep working on it, and If find something IŽll post it.

Cheers
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rH
 
Old 03 March 2013   #3
I would just duplicate the mesh connect the outMesh to the inMesh them smooth the duplicate mesh. Then delete the polys i don't need.

For the cloth that close to an nRigid and stays that tight. I would turn off collision on the nRigid and use a slide on surface constraint. SOS constarint have a biult in collision that is optimized for this type of work.

HOWEVER handle with care.
SOS uses "Local Collide". I find this feature is faster than regular collision. However if it does not work. The results are usually REALLY bad.
So if you do use this method. Be aware that when it messes up. Try turning this off and see if your problem go away.
 
Old 03 March 2013   #4
Thanks. IŽll try all that and iŽll post results.
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rH
 
Old 03 March 2013   #5
why are you trying to simulate such tightly stretched cloth anyway? doesnt seem like it would have much appreciable movement. you would be better off if you used nCloth or muscles to get some secondary motion on the thigh itself.
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Old 03 March 2013   #6
Originally Posted by stooch: why are you trying to simulate such tightly stretched cloth anyway? doesnt seem like it would have much appreciable movement. you would be better off if you used nCloth or muscles to get some secondary motion on the thigh itself.


That was my first thought. I did some test without nCloth. Doing some blendshapes to simulate wrinkles looks good. I havenŽt dismiss the idea. But if you set up nCloth right it looks a lot better. Maybe I am wrong, but in the avengers, hulkŽs pants are simulated, and they are thight.
I am trying to do it with nCloth at the moment. It is true that it is a pain, but if it work out it will look great. If it is to complicated, IŽll do it without nCloth.
I guess that in the end I might use a combined system.WeŽll see
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rH
 
Old 03 March 2013   #7
well it depends greatly on your targeted motion then. ie, your character would have to be doing very rapid and sudden changes of movements with the camera focused tightly upon the crotchal region while experiencing slow motion. I suppose if you have a lot of free time, rigging tight dynamic pants would be a good learning experience its definitely going to be fun in sub step land with a healthy dose of input mesh attract. Might even have to use a wrap deformer driving a high res mesh with a much lower res ncloth (which coincidentally may smooth your anomalies out as well).
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Last edited by stooch : 03 March 2013 at 04:57 PM.
 
Old 03 March 2013   #8
In that example it looks like you are using vertex collisions on the nRigid. Use full surface collisions on both the nRigid and the nCloth.

Another possibility is that the collision thickness is large and start position of the cloth is much closer than the combined collision thickness. Turn on display of collision thickness for both the cloth and the nRigid.

The cloth when colliding looks at relative distances between components at the start frame (vertices to faces, edges to edges, etc). If any of these distances at the start frame is less than the collision thickness it lowers the collision thickness BETWEEN those components pairs. This keeps the cloth from blowing up at the start frame in overlapping regions, but means that as it moves the relative thickness of the surfaces may appear to change, and that could be the problem you are seeing. (increasing the colliding mesh resolution might help, but you should be able to avoid the problem without resorting to that)

For a tight garment you could initially model it slightly loose then make the rest length scale something like .8 to shrink it onto the body( like tight spandex ). It helps when doing this to make the stretch resistance lower so it doesn't fight collisions too much. If the stretch resistance is very high you would need higher substeps to better handle the collisions.

If the size of cloth faces are smaller than the body mesh faces then you may still see the lack of smoothness in the body mesh. For a tight cloth it would be good to have both meshes at about the same resolution.
 
Old 03 March 2013   #9
Originally Posted by Duncan: I (increasing the colliding mesh resolution might help, but you should be able to avoid the problem without resorting to that)
.


Duncan: exactly, thatŽs what I am trying. Thanks for your advice. IŽll try all that and post results.

Stooch: I donŽt it has to be that specific,with slow motion, or in a very close up shot to notice the difference between a simulation and a skinned mesh, because it is not that tight after all. I want to do a material like this one. Maybe if it was a harder surface, like jeans simulation would be pointless. WeŽll see.

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rH
 
Old 03 March 2013   #10
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