Okay.
So I went to see a friend of mine last night, and we got a little into our cups...
And decided to go play with Poser.
In the middle of trying to put some dress on M4 (don't ask, there was alcohol involved), she says "I can never get the dresses to stay on V4, they fall off, we should try it on M4."
Took me a minute to work out what she was on about, and it was some dynamic dress. Sorry, I don't know who it was by, or what it was called.

Anyway, here is the thing (I watched this...)
She put the dress on V4. Does all the bits to get it clothified and yup, it's there, just fine, covering all the bits.
Applies the pose in the last frame. Adjusts for rotation.
The pose has V4's arms at her sides.
Then she calculates.
As we watch, the dress slowly slides down V4's body, baring her to the navel.
We try with harsher cloth settings. (We were sobering up somewhat, because it was darn annoying) Same thing.
We have the thing almost stiff as a board.
Same thing.
It does not stay on V4's boobs.

So, apart from gluing the thing to the top of her breasts with contrained groups (which make it look weird, because the rest still slides down), what is going on?

I'd call and ask, but the silly girl went on holiday today.
Still, I've had the same thing happening with freebie dynamic stuff, and I really don't know what to do with this.

Anyone able to explain how to stop this?

Silke, without seeing the dress I need to make some assumptions from your story.

1 this was a strapless/armless dress?

2 what do you exactly mean by "adjust for rotation"? If you have the dress fitted to the figure in the first frame, and the figure rotates in some way to assume the final pose do you mean you are also manually adjusting the dress to that rotation? Rather than letting the dress drape dynamically on it;s own s the sim progress'?

When you say you used "harsher setting" I assume you mean you increased the stretch resistance and the stretch dampening, di you also increase the static friction and dynamic friction settings? It;s been a while since I used dynmics clothing but these settings may be the key to your problem.

3 If you are using Poser 8 there is a new check box on the cloth room controls called "Collision Friction", you might want to check that on and see if it helps as well.

In ALL cases me totally sure that the dress does not poke into any vertices on your base figure (or vice verse) as this can cause a great deal of trouble in your sim.

If you can give any more specifics on your experiment, such as settings used and if possible a screen cap before running the sim and after running the sim I can try to duplicate it and give you some better answers. (Don;t worry about who made the dress, if I can see a pick I can probably model SOMETHING that is reasonably close to experiment with).

Wish I could give you screenies, but I can't. I don't have that dress.
We tried three different ones.
One had 2 arms, but they were already wide and resting on her bicep.
So with arms down, the sleeves slid down and the dress fell off. Well. It didn't "fall off", but it dropped below V4's boobs. Not quite the effect you look for in a gown lol.

When I said adjust for rotation, I meant because V4 was rotated a bit in the last frame, we applied that rotation to the first frame, thinking maybe the dress is twisting off and that's what's causing it -- didn't make a blind bit of difference.

The harsher setting... yeah, we cranked up the cloth settings until you had about as much movement in the cloth as you get in leather -- and it still slipped below the boobs.
If we kept the arms up, the dress stayed almost on the boobs, but not quite.

The strapless one... ferget it. It just landed below her boobs every time. We couldn't get the darn thing to stay on her.
I got a feebie one here and I'm running that through a simulation atm... and it seems to behave.
It has arms though.

I can only assume it was the way that dress was set up. (They were all evening gowns, if anyone has an idea of which dynamic ones they might have been... holler. I should have taken the name down lol.)

Collision friction on or off made no difference.
Poking in or not made no difference either. :/
In fact, having the dress stick inside her boobs made a tiny bit of difference -- until the last couple of frames when it all slipped half way down her boob again.

Quote - If anything else fails, position your figure with her/his arms up, see difference between left and right arm in render ...

Yeah, but you see, where your right arm is down and the strap is down her arm, you still have the top of the dress on top of her breast.
That's not what was happening with those dresses. If the arm were this far down (which at one point it was) then that side would be underneath her breast, just dangling there.
I know it wasn't a freebie.
I'm so going through the stores now lol. I know I've seen it, even lusted after it, but never got it.
Right now I'm glad I didn't, after seeing the struggles last night.

Constrained groups.
http://www.philc.net/tutorial6.php

add the very top of the straps , or neckline , to the constrained group. That should lock in place if in collision.  You only need a few vertices.

Also, different people may do it different ways, but imo do not rotate or parent or whatever the dynamic cloth, it should never be necessary.  Start the simuation at frame 1 with zero pose, zero morphs, end the simulation at frame 30 or 60 or whatever with the character in the final pose - unless the simulation settings are just wrong, or the animation is too short, then the cloth will flow around the character pretty much the way it would in the real world (within reason).  If you have the character doing cartwheels it may be a problem, but pretty much any standing pose, not a big deal.

Tried that.
That was my first thought too, but while the strap stayed on the shoulder, the bodice still slipped below the breast.
However, I found the dresses, after digging through the dynamic stuff in the marketplace.
At least I think those were it. (Not 100% sure)
It was the glamorous collection, I think.
Looking at the promos... some of those poses... look incredibly dodgy, with the front slipping very very low to the extent of near exposure, and to me it looks like they are only held up by sheer chance (and the position of the arm). (Sorry, Corvas, maybe you can shed some light on what was going on.)

As I said, I was tempted, but the two of us (though rather sozzled) could not get them to stay on her chest, unless we lifted her arms.
Not even with a constrained group on the shoulder -- and lets not even go to the strapless one, we gave up on that one inside of 10 minutes. It would not stay on.
Again, my apologies to Corvas, because I am really only guessing, but that's kinda what the dresses looked like...
Frankly... that promo with the purple dress... I DO wonder what that would look like from the front, because it looks... uh... yeah.
I also notice that every promo has a disclaimer that the dress was fiddled with in a 3D app after simulation... and postwork to fix nipples...
(The promo behind the materials looks well dodgy, if you ask me...)

I'm really sorry, I don't mean to tear into something that looks so stunning, but we just couldn't get it to work, which makes me wonder if it was the dresses, rather than us.
I just simulated a free dress from Poserworld, granted, that one has arms, but it didn't fall off... Nor did the freebie one from Tabala, even when I had V4 lean forward.

If you think that constrained group looks weird, add dummy props (for example balls) parented to shoulders. Place them where you think that straps should stay. You can make them transparent or invisible before rendering scene.

Oh that's a cool idea. I hadn't thought of that!

There is no reason you can't put constrained verts along the bust or anyplace else - you just don't want to do tons and tons of them to avoid the "thumbtack" look. Look at some of the pics here:
http://sites.google.com/site/fleshforge/Home/free-stuff-1/gillian-dynamic-dress-v4

Quote - Tried that.
That was my first thought too, but while the strap stayed on the shoulder, the bodice still slipped below the breast.
However, I found the dresses, after digging through the dynamic stuff in the marketplace.
At least I think those were it. (Not 100% sure)
It was the glamorous collection, I think.
Looking at the promos... some of those poses... look incredibly dodgy, with the front slipping very very low to the extent of near exposure, and to me it looks like they are only held up by sheer chance (and the position of the arm). (Sorry, Corvas, maybe you can shed some light on what was going on.)

As I said, I was tempted, but the two of us (though rather sozzled) could not get them to stay on her chest, unless we lifted her arms.
Not even with a constrained group on the shoulder -- and lets not even go to the strapless one, we gave up on that one inside of 10 minutes. It would not stay on.
Again, my apologies to Corvas, because I am really only guessing, but that's kinda what the dresses looked like...
Frankly... that promo with the purple dress... I DO wonder what that would look like from the front, because it looks... uh... yeah.
I also notice that every promo has a disclaimer that the dress was fiddled with in a 3D app after simulation... and postwork to fix nipples...
(The promo behind the materials looks well dodgy, if you ask me...)

I'm really sorry, I don't mean to tear into something that looks so stunning, but we just couldn't get it to work, which makes me wonder if it was the dresses, rather than us.
I just simulated a free dress from Poserworld, granted, that one has arms, but it didn't fall off... Nor did the freebie one from Tabala, even when I had V4 lean forward.

I just finished a render with one of the Glamorous Collection dresses, and I know exactly what you mean.  I had to play and play with constrained groups in order to make it not slip below the bust line.  By selecting all of the collar all the way around as well as the shoulders, I got it to finally behave.

Ah, so it wasn't just us then.
I felt like a complete idiot and was sure I was doing it wrong. (Not aided by Amaretto...)

did you  try cranking  up  the static  friction  to  the max in  the "collide against " menu....

I don't know if that  was part of what  you  called   - "setting harsher cloth settings"

And another dynamic cloth fan is born.

I try to clothify items that have a convenient material group that I can constrain.   Anything else can be hit or miss, but at least miss can be entertaining.  Sometimes.

I've never tried drapak's prop trick.  Sounds interesting though.

Actually I have been a fan of hybrid clothing, especially for stuff like strapless dresses, conforming to the waist and dynamic below that. that way the bodice can be as tight fitting and sculpted as wanted and the skirt free to flow. That way the top always stays in place. This can also work for small over the shoulder straps and tight sleeves as well.

Constrained or choreographed groups work well ony if theirs vertex have distance from body polys equal to collision offset. It means that you can use them only with cloth made for particular figure. Another way constrained groups looks weird - strange peaks or holes.
If you want to use clothes from one figure to another you have 3 choices.

1. Add dummy props in crucial areas. You can use it either to obtain special effect. Props which crossing clothes can be use as a constrained groups changed during animation. For example you can "pin" sides of open shirt with cylinder prop (stick shape) to chest of the figure. If you make it invisible in some frame, at this moment you unzip button and open shirt.

2. Using cloth room fit it desired figure (see my tutorial steps 1-9 http://www.renderosity.com/mod/tutorial/index.php?tutorial_id=2154)
   Then import cloth which you fited for pose "0", select constrained or choreographed groups and calculate dynamic.

3. Edit cloth obj in modeling program. "Close" holes of collar and arm. Polygons which cross through body will hold cloth in correct place - some verts are "under skin" and cannot slide down.
   It can be done only with high res figures and clothing, calculation takes a lot of time, sometimes (in very dynamic animation) verts can be throw out from skin.

i avoid constrained in general. changing your folds won't do a thing about how it slips.  you need to change friction.

look up the collision friction in the manual.  it probably doesn't do what you think it does.  what you're toggling is whether you use the individual collision friction settings or whether to use the friction settings in the dynamic set.  if you don't change those from the default, then you won't get any change in performance. 

if you have one piece of clothing, and one prop or figure you're colliding against, it doesn't make a difference.  you might as well just use the main friction settings.  but the default won't do about anything.  i got fairly decent results when i had both dynamic and static friction at 0.9 for something i didn't want to move where it was against the skin.

i'm away from home and on my mom's laptop so i don't have reliable access.  pardon if i don't reply soon.

I had the same problem.  I posted about it and got some really good tips.  My problem ended up being a cloth density issue.

http://market.renderosity.com/mod/forumpro/showthread.php?message_id=2444578

Also, here is a thread that has cloth room bookmarks.  Lots of helpful information in there about all kinds of things.

http://market.renderosity.com/mod/forumpro/showthread.php?thread_id=2739159

Have you tried raising the dress slightly so that  it settles down on the breasts--sometimes that works.  Jan

Everyone seems to have missed the basic problem here. The dress is too large and loose for the figure and would fall off a real person in exactly the same way. The simulation is accurate.

not necessarily.  Silke never mentioned the dress drooping anywhere, just sliding off the body.  unless you have information not in this thread?

by default, i find the friction is unnaturally low.  like the smooth side of satin on metal.  i've had  to raise it to get it to behave naturally.  by a lot, in my experience.  even then, i don't find it works perfectly.

We need to pester PhilC to make an addon to WW2 or a new WW3, that when you convert you have the option to convert to a hybrid. Remove the appropriate bones and make the upper part conforming for all the reasons mentioned above. It should be a much easier process then it is.

I convert a lot of conforming clothes to dynamic. But I really like hybrids a whole lot more if the cloth is strapless or has just shoulder straps. Long sleeves, I just convert to a prop and it should be good to go, most of the time.