I'm wondering it has something to do with the cloth trying to collide with a layer of itself underneath and the figure at the same time, or if backfacing polys could be the culprit.

I have a fairly low fold resistance, which is how I want it to get nice looking drapes (And giving it higher fold resistance didn't prevent the issue from happening anyway)

Anyone every discovered a solution to this?

I predict you are doing nothing wrong, people will suggest thngs for you to try, nothing will fix it, and you should post a bug report, but like dozens of others, you will not, and SM will continue to not address this.

Sounds like posting a bug report may not be a bad idea in the long run. So is it a known issue?

It's known to me, but not to SM. Until I showed it a few months ago it was not a known issue here in the forums, from the standpoint of somebody with a measure of confidence and certainty can show that something is broken.

I did not report it to them because I don't care. And I'd rather they work on things I care about. So reporting such as this will potentially derail things I want them to work on.

If you care, you should report. They have meetings all the time where they decide what to do and what not to do. They do not decide this based on forum or chat. They base it on official communication with them, from their customers, who care to take the time to speak to them about defects directly.

Have to agree with BB on this, A bug report is the way to go, and now might be a great time for it, the cloth and hair rooms in Poser seem to be lacking in the new DAZ studio and ANY improvements in those areas might be welcome at SM. Also grab your friends and if they see the same results have them also post official reports, numbers sometimes help.

In the meantime if you are working on a still frame render you might try using the morph tool "smoothing" function set at VERY small strength after you finish your sim, sometimes this will relax the vertices and fix the problem, however over doing it may loose the fold, so go slow. 

You can check the boxes for all the collision types, and that may help some of it.  Increasing collision offsets may also help.

Bug report definately cant hurt.

There ya go - just as I predicted. Heheh. As if I did not try every possible combination of collision options.

Cloth self-collisions - hmmm - I am not getting self-collisions - let me try with this box checked - nope - unchecked - nope - hmmm this checkbox seems to do nothing related to its label.

A lot depends on the mesh density to determine if the other collision modes will help.  Changing some of the cloth attributes can also limit the very sharp bends. 

The easy way is to put the final cloth into a modeller and fix it there.

It's definately a bug, report it so they will at least know it's there.  Why continue to look for a work around when it needs to be fixed?

I am making this outfit for a project of my own. It drapes very nice, other than the discussed bug that appears in a lot of poses. Even though this particular bug is somewhat prevalent in it, I'll still offer it as a freeitem for the community. It works quite nice with a little bit of postwork.

And I'll make a point to submit a bugreport while I am at it as well. :)

I've submitted a bug report for this, too!

Increasing the collision offset usually fixes the issue for me.

Is the item you're clothifying designed for use in the cloth room or did you clothify a conforming mesh?

It's designed for the cloth room. Increasing the collision offset makes no difference, and I don't want it too high either, because it will look unnatural.

It becomes a case of diminishing returns. Fiddling parameteres may improve some of the defects but it can take a lot of time. For the models I make I would probably take that area and subdivide each quad into 4 .

It's already quite dense, 26k or so, to get the nice drapes.. :) The freeitem will probably be up in a day or too, so anyone who wants to experiment with it will be more than welcome.

Another thing you might try is making that area either a soft decorative group or even a constrained group. 

Won't work on loose fabric that's supposed to drape. The waistband is already constrained.

I had the same problem with nun habit for Antonia. Collision offset does not affect cloth self collision. Creating soft decorated group does not help neither.

I do not know exactly what part of cloth poke through, but you can create 2 simulation. Cut this dress obj along waist line. First calculate skirt, later shirt. Then you can set offset.

Amanda at SmithMicro got back to me on the cloth collision issue today.  She wanted an example of the problem, a scene inventory, and an outline of my procedure and settings.  That seemed reasonable to me. I strongly recommend that any of you who've experienced this do the same thing I've done and submit a report.

The cloth is submitted in my freestuff now, so feel free to play around with it. :)

Anupaum, I have been quite busy lately so I haven't had a chance to submit a report, but I will when i get the chance. My free item would work perfectly well as an example for this.

Attached Link: Lili's Angel Dress

I've tried to insert images into this forum several times without success, but this time the "Attach a File" link on the bottom actually worked for me.  Progress!

This is a beautiful dress prop, Grappo!  Thank you!

Beautiful picture!

I think the issue appears more likely in certain poses also. Did you use my default settings that came with it, or Poser's default settings?

Thank you!

I used Poser's default settings.  I was going to use the ones you suggested in the ReadMe, but after saving, Poser crashed . . .  (It often does that.)

I mean the cloth settings that come with the dress. Unless you use an old version of Poser, the cloth settings are saved in the cloth prop. (Like fold resistance, density etc)

Oh!  I've learned something new, then!  I didn't adjust anything other than the collision offset and collision depth.

I got another response (this one from Matt Ko) from SmithMicro.  This is what he said:

"Thank you. I have downloaded Grappo2000's dress from your first image and that problem appears to be caused by the constrained groups she made in the waist area. Used correctly, constraining should work fine, but there can be cases where using constraining in awkward areas or overusing constraints can cause polygons to be positioned in an unnatural way that makes calculations more difficult, thereby creating unpredictable results."

I've also had this problem, so I need to go through my old renders and find one that plainly illustrates the issue.  They need a scene inventory to evaluate what's going on.  I've read complaints about SmithMicro, but they've never experienced poor service from them.  If the rest of you are having this problem with cloth simulations, I think they should hear from you, too!

I never bothered chasing cloth room bugs , I regard it as pretty remarkable for a program of Posers cost. :)

Collision depth /offset should work on cloth self collisions because its how I get clothes on the floor without it being a flat puddle.  

Fold, stretch, shear values in the cloth parameters can make significant changes

I completely agree about awkward constraints causing problem. But a simple narrow waistband? That's one of the places where constraints are most commonly used.

I will get in touch with them this weekend.

if the mesh is not going through another mesh then this doesnt happen a lot of times.

a lot of clothe engines have this inside. the software knows what to do when the two objects dont touch but go through eachother .

this

http://graphics.pixar.com/library/UntanglingCloth/paper.pdf

I don't really understand what the deal is in this situation.

whait a minute. my english is bad.

in your frame 1 your cloth already intesected with her body? her skin was looking through the cloth?

Not looking, but poking through.

if its already poking through in your first frame then this is a mistake. it should not poke through. fix this with the morph brush.

The problem is, I was told that the figure was poking through, but I couldn't see where.  Also, when I do simulations with female figures who have big breasts, they are OFTEN not completely covered through the draping process.  However, the simulation will cover them.  So why is that true of breasts, but not other body parts?

Quote - The problem is, I was told that the figure was poking through, but I couldn't see where.

If the pose in the first frame was the one in the image a few posts earlier, it's most likely that the hand on the hip was the problem (either by intersecting just the dress, or worse interpenetrating the thigh as well).

This is where forums get frustrating!  I've been working with dynamic cloth simulations since P6, and I use them far more than I use conforming clothing.  (Of course you couldn't know that, given that you don't know me.  I'm not being testy here, just illustrating how difficult it can be to communicate through a computer.)  In order to minimize problems with cloth simulations, figures must begin in the classic "zero" pose at the outset.  I usually set the final pose in frame 15 of a 30 frame simulation, add the cloth prop, drape for a few frames, then simulate for 30.

Now, the image above, that shows the girl with her hand on her hip, had NO issues with offending polygons protruding through the cloth mesh.  If you scroll back earlier, I posted an image of a girl sketching on a bed.  THAT image shows the polygon problem, and that's the one SmithMicro's experts told me had the figure poking through the cloth in frame one.  I can't see the offending "poke through," but in the image of the girl with her hand on her hip, she wasn't completely covered until frame 24.

I'm puzzled by the claim that any of the figure's polygons that intersect with the cloth mesh at frame one will result in the cloth polygon on cloth polygon problem that Grappo illustrated at the outset of this thread.  I used the image of the girl with her hand on her hip to demonstrate that if breast polygons are intersecting (sticking through) the cloth mesh in frame one, Poser Pro 2010 (and even P6!) will calculate and compensate for that.  So, to claim that figure polygons intersecting with cloth polygons creates the problem that Grappo outlined makes no sense to me.

I have seen exactly what you are talking about happen and have never figured out why. Some cloth where there is poke thru at frame 1 will fix it's self with a few drape frames and some will not. If the figure is sticking thru the cloth what I tend to do if I can't reposition the cloth to fit is scale the figure down in Z and X in frame 1 and then put them back to 100 percent in frame 15 or so and or that is the same frame I add body morphs. I never start with body morphs in frame 1. Typcially I let the cloth settle for the last 15 frames unless the character is supposed to be showing action like running, walking swiftly or falling.

Where the cloth does not self correct with a few drape frames for me most of the time has to do with the arms and hands and or shins and feet. Typically if it is the torso only a few drap frames and the cloth jumps out from inside the body. But again I have cloth that does not behave that way and some that do.

yes its true that in some situations even if there is poke throu in frame one it will work. BuT TO BE SAVE make sure that there is no poke throu in frame one. hehe ;)

Here's the latest response to my query from SmithMicro:

"I had one of the Engineers look at this issue. They reported that this appears to be a setting issue with the Dynamics. Try setting the collision offset and collision depth to be a bit higher- 2, say, instead of the default 1- should resolve this."

Isn't that what BB predicted?

Quote - Here's the latest response to my query from SmithMicro:

"I had one of the Engineers look at this issue. They reported that this appears to be a setting issue with the Dynamics. Try setting the collision offset and collision depth to be a bit higher- 2, say, instead of the default 1- should resolve this."

Isn't that what BB predicted?

Collision offset and depth to 2?  That sounds rather extreme to me (And not pretty for most clothing) I tend to stick under 0.6 for most clothing. What settings did you use on the shirt image?

Usually, I use .2 and .25 for the offset and depth.  To my eye, those settings give the most realistic fit.  I have an animation that uses 1 for collision depth on the skirt, because the poor girl's legs kept poking through the skirt hem:

http://www.youtube.com/watch?v=NQDyKbKb2cE

But I can see the gap between the fabric and her hip with disconcerting exasperation!

The folding polygon issue I haven't been able to resolve yet, but if you get pokethroughs, I've found that increasing the amount of steps in the cloth calculation settings can actually help quite a bit.

Another way to tackle pokethroughs is to ensure that the cloth has enough polygons to properly drape around the figure. A lot of dynamic clothes have far too few faces where needed. (Elbows, breasts, kneees etc.)  

In the animation I mentioned, I bumped up the steps to something like 20.  (It took a long time to calculate.)  Poke through is generally not a big deal for me, but the polygon issue that you mentioned often IS, and there seems to be no solution for that problem.

It seems to have something to do with self collision. Maybe it tries to collide with itself and the figure underneath. I was facing this problem when I played around with making a multilayered skirt. I couldn't get the collisions to work properly with self collision. The band of a skirt underneath would poke through the top skirt (soft decorated), the bottom skirts would also poke through as a dynamic group. I tried high density models both as quards and triangles and the same problem would arise (sometimes in different manners, but it persisted)

I typically have this issue with nightgowns, or other diaphanous cloth props that feature multiple folds.  So, either the people at SmithMicro don't understand the problem (which is likely, from the way they reply), or they DO understand and don't want to address the issue.

Yeah. Multiple folds or multiple layers is where I get the issues 100% of the time as well. I'll see if I can dig out the multilayer shirt somewhere and post. It's a perfect example where the same thing happens with multiple layers.