-RESOLVED- Simulation bouncing all over the place

friqenstein

Hi,

So, here's the thing... I have a G8.1F figure freshly loaded into the scene. MOve to frame 30, set a VERY BASIC STANDING pose. Then, apply clothing and simulate the very short basic pose so the clothes can drape accordingly.

Now, 90% of the time, this works just like expected, nothing out of the ordinary. However, with some product, and for some retarded reason, the product clothing tends to 'bounce' all over the place; as if gravity has been flipped upside down for that 1 article of clothing while everything else sims perfectly normal. WTF? What gives? It only seems to happen with certain clothing products.
No, I've not adjust anything with the dynamics of the d-force settings, everything is default, hence the first sentence.

Why is it that some clothing products don't seem to work properly with simulation, even though they product is advertised with D-force? The product is even shown with 'simulated results' indicating that the cloth is supposed to flow/drap properly while using d-force, yet it doesn't.
Is it that the creator doesn't know wtf they are doing, something is glitched in their product, or what? It is highly annoying to purchase a clothing product only to have it be demmed utterly useless because you cannot sim it in any scenario whatsoever.

Any insight would be greatly appreciated.

felis

It is not clear to me what you are observing.

Does the clothing interfere with other objects? Can the hair interfere?

Try to show a scrrenshot of what you are seeing, or mention a clothing item that misbehaves. Then other can see if they have similar behavior.

Taoz

dForce seems to be pretty unpredictable, a piece of clothing may work with one character, or one pose, and not with another, using default settings. 

TheKD

Dforce has been hit or miss for me lately since updating. I was trying to simulate one dress yesterday, and as soon as the sim started, it would immediately just float toward the floor as if the figure wearing it wasn't even there.

friqenstein

@felis, okay, picture this. Your figure is standing still, no movement. You put a shirt on her and hit sim, bones memorize off since still in Zero pose. As it starts to sim, the bottom edge of the shirt, the shirt-tail, just floats upward, as if there is some sort of updraft blowing it preventing it from falling/draping naturally.

If I put any other clothing that I have already used and know sims fine, I delete the 'faulty' shirt, apply the known good article and sim... works perfectly.
Delete the good one, apply the suspect one, leave in Zero pose then sim.. floats up, or sometimes sideways.

Here is one particular product that does it. The shirt and the tie just float for no reason.
https://www.daz3d.com/dforce-long-shirt-outfit-for-genesis-8-and-81-females
If I use just a plain basic 8.1F figure, it doesn't always float up, but it will drift sideways, even in Zero pose, instead of falling/draping naturally downard.

No hair applied, no undergarments, nothing else is in the way.

@TheKD, I've had that happen, float to floor, then check the item to ensure the colision item was set; sometimes the creator seems to brain fart on this option and I have to manually set it, but at least it is fixable.

Edited to fix link - mod.

felis

I don't have that product. But I would assume that it should be a fairly simple mesh.

The only thing I can imagine for that behavior is if there is an area where the vertex distance is smaller than the collision distance, so it will build up energy.

When you start the simulation does it then come with a long list of springs violating collision distance (it is before the simulation start, when it is preparing the simulation)?

You are using timeline. Is it from the start of the timeline it acts up weird?

crosswind

Surfaces tab - simulation properties of the shirt, check if self collision is on, then turn it off. See if it works.

Richard Haseltine

felis said:

I don't have that product. But I would assume that it should be a fairly simple mesh.

The only thing I can imagine for that behavior is if there is an area where the vertex distance is smaller than the collision distance, so it will build up energy.

That would be my first thought, too. Do you get warnings about springs being shorter than the minimum offset before the simulation starts in earnest?

When you start the simulation does it then come with a long list of springs violating collision distance (it is before the simulation start, when it is preparing the simulation)?

You are using timeline. Is it from the start of the timeline it acts up weird?

Richard Haseltine

Richard Haseltine said:

felis said:

I don't have that product. But I would assume that it should be a fairly simple mesh.

The only thing I can imagine for that behavior is if there is an area where the vertex distance is smaller than the collision distance, so it will build up energy.

That would be my first thought, too. Do you get warnings about springs being shorter than the minimum offset before the simulation starts in earnest?

To nswer my own question, yes there are a fairly long string of those - but the mesh isn't that dense, and if I simulate it in isolation I don't get any weird lifting (it hangs in place for that because only the lower prtion is dynamic).

When you start the simulation does it then come with a long list of springs violating collision distance (it is before the simulation start, when it is preparing the simulation)?

You are using timeline. Is it from the start of the timeline it acts up weird?

Richard Haseltine

Select the shirt in the scene, select the shirt in the Editor tab of the Surfaces pane, type offset into the filter box at the top and then lower the Collision Offset value - 0.1 helped, 0.05 seems to fix it - however, a lower value does increase the risk of poke-through.

Dartanbeck

I disagree with the comments that dForce is unpredictable. That's very much the opposite of what I observe.

 

Things that can wreck a simulation:

The wearing figure colliding with itself - common when the arms bend too close to the body or any joint bend in the collision closing too far onto itself

• Quick Fix - Temporarily alter the bends to prevent the clothing from misbehaving during the simulation, then set it back after the simulation is complete

Too many Collision Items in the Scene - common problems I've seen from many folks

• Quick Fix - Only load the dForce items being simulated onto the figure - leaving the rest of the scene empty
• Another Option - Make Invisible anything not absolutely Required for the simulation
• Also - Don't simulate more than one complex item at the same time - Use "Freeze" and Hide to work out indivual simulations separately

 

Be mindful when working out simulations of any kind. Take care and focus on what you really need done in your scene.

 

Matt_Castle

dForce is a bit finicky at the best of times - specific poses and morphs can cause mesh to get scrunched , and changes to the algorithm may cause some products that worked fine in older versions of DS to need some fine tuning in newer versions.

If you have something that is genuinely buggy on the base figure shape in the base pose, then I suppose put in a bug report.

In terms of what might fix it, I'd guess the same as others. Reducing collision offset is usually the fix for clothes with a mind of their own. You may indeed have problems with poke-through, but increasing collision resolution and quality can fix that.

And of course using smoothing, but for the love of sanity, turn off the smoothing during the simulation. It's recalculated each tick and is almost entirely ignored despite that, so it's a massive increase to simulation time.

Dartanbeck said:

I disagree with the comments that dForce is unpredictable. That's very much the opposite of what I observe.

It is somewhat unpredictable, given that - contrary to what you would normally expect from a computer - running an identical simulation again does not create identical results.

I have sometimes had a simulation explode, then run it again with absolutely no changes and it's then been fine.

 

Havos

Richard Haseltine said:

Select the shirt in the scene, select the shirt in the Editor tab of the Surfaces pane, type offset into the filter box at the top and then lower the Collision Offset value - 0.1 helped, 0.05 seems to fix it - however, a lower value does increase the risk of poke-through.

If the clothing item is just 1 layer then having a low collision offset generally does not cause any issues, however for multi-layered, then as Richard says, this may cause one layer to poke through into another.

Dartanbeck

Addendum: While I find dForce to be fairly predictable, what is quite unpredictable is how various artists set up "dForce" clothing/items. 

crosswind

friqenstein said:

@felis, okay, picture this. Your figure is standing still, no movement. You put a shirt on her and hit sim, bones memorize off since still in Zero pose. As it starts to sim, the bottom edge of the shirt, the shirt-tail, just floats upward, as if there is some sort of updraft blowing it preventing it from falling/draping naturally.

If I put any other clothing that I have already used and know sims fine, I delete the 'faulty' shirt, apply the known good article and sim... works perfectly.
Delete the good one, apply the suspect one, leave in Zero pose then sim.. floats up, or sometimes sideways.

Here is one particular product that does it. The shirt and the tie just float for no reason.
https://www.daz3d.com/dforce-long-shirt-outfit-for-genesis-8-and-81-females
If I use just a plain basic 8.1F figure, it doesn't always float up, but it will drift sideways, even in Zero pose, instead of falling/draping naturally downard.

No hair applied, no undergarments, nothing else is in the way.

@TheKD, I've had that happen, float to floor, then check the item to ensure the colision item was set; sometimes the creator seems to brain fart on this option and I have to manually set it, but at least it is fixable.

Edited to fix link - mod.

 Turn Self Collide Off...a commonly-used trick.

crosswind

Dartanbeck said:

Addendum: While I find dForce to be fairly predictable, what is quite unpredictable is how various artists set up "dForce" clothing/items. 

I fully agree on the point of "fairly predictable and stable"  through my exp.. Conservatively, same item property settings + same sim. settings + same dynamic surface settings can result in 99.9% same sim. result. If one has interest, he/she may carefully compare the sim. results in viewport, even export the dforced item(s) to obj file(s) to compare vertex positions.

Well, there is always an exception to everything....then we check case by case, for instance, the typical case on timeline with geometry intersection that may results in 'tiny explosion'...and unique cases in SBH...

As for the 2nd point, it's always commonly seen...

friqenstein

@crosswind,

Thanks for the suggestion; I'll give it a try tomorrow.. currently have a large queue rendering over night.

TIA.

Dartanbeck

 Loves me my dForce!!! 

friqenstein

@crosswind,

I've disabled the self-collide and that shirt seems to stop floating up... thanks for the insight.
 

crosswind

friqenstein said:

@crosswind,

I've disabled the self-collide and that shirt seems to stop floating up... thanks for the insight.
 

Great! You're welcome.