# How to make Poser's Cloth Room work for you every time.

• Watching how this is unfolding (har de har!) Errol, this is an EXCELLENT way to start a thread. "Has anyone got tips on..." some great stuff coming out here. Perhaps we should start a thread like this once a month on different topics.

• @matb
I think we talk of different things here. I had taken 'retain volume' as 'maintaining a constant volume'. Like a waterbed: press here and it pups up there.
I assume you refer to 'applying a constant surface pressure', like a water bed that is connected to a water reservoir of constant pressure. When you push on the surface of the bed the water you displace simply moves into the reservoir.
I have never actively used bulletphysics but as far as I can see the 'internal pressure' parameter does what you are looking for (Poser reference manual, Chapter 25/page 616):
Internal Pressure: (Soft Body objects only). Specifies the internal pressure of the object. Objects that have a greater internal pressure will collapse upon themselves less than objects that have a smaller amount of internal pressure

Consequently it would/should be easy to make the setting available in the clothroom. The function is much used in Marvelous Designer so yes it would be useful t have.

Retaining constant volume during a simulation is a different matter. It makes sense only if the cloth represents an enclosed volume or the free edges rigidly constrained. Compuationally it would require a surface integral being calculated every simulation step and the internal pressure corrected according to a penalty function, that could for example have the form of Boyle's law. Now we are in the realm of physics: the surface integral used to calculate volume could be an implementation of Archimedes' law.

• For the sake of argument, and complexity, while Bullet Physics may be used in conjunction with the Cloth Room, I have no intention to cover it in a tutorial on the Cloth Room at this time. I think that for many users the Cloth Room is already complex enough without adding features to it that aren't even a part of the Cloth Room.

• Everyday clothing does not "do" volume retention, so there's no need for it in a cloth room either.

• @eclark1849 As I understand it the way that bullet physics works would be counter productive in the cloth room unless you are doing a basic animation ... as the cloth doesn't actually "touch" the figure but the "shells" that "attach" to the figure for faster processing like when used in a gaming environment.

• @eclark1849 As I understand it the way that bullet physics works would be counter productive in the cloth room unless you are doing a basic animation ... as the cloth doesn't actually "touch" the figure but the "shells" that "attach" to the figure for faster processing like when used in a gaming environment.

Haven't used BulletPhysics, yet. But, are you saying that bulletphysics uses "hitboxes" for the objects/calcs that it does? It generates these on its own or does the user? (Not meaning to go deep into bulletphysics, 'cause that'd need a new thread.)

• Did you know?

That Poser has changed the file format on dynamic hair and dynamic clothing? I rarely buy dynamic clothes because I can so easily make them myself, so when I save them to the library, it's usually as a prop. So as I'm reading the reference manual for the Poser 11 Cloth Room, I see this:

"Beginning with Poser 11 and Poser Pro 11, hair and cloth dynamic files are saved with an .abc extension (Alembic format)."

If this goes like in the past, this will be mostly ignored, particularly by the stores and vendors.

• @eclark1849 Interesting. Wonder why they did that? Would I be correct in thinking that alembic is a more universal format?

• @vilters No that's a good point, but items like quilts and pillows do, so it's useful occasionally. Even towels and blankets which are constructed as double-sided shells could perhaps avoid vertex intersection problems with that technique.

• @F_Verbaas I'm afraid the science part of your answer was beyond me (although I appreciate you trying! :-) Yes, the bullet physics might well be a good solution. I've found that a little frustrating to use as the parameters seem to interact so bizarrely, but perhaps I SHOULD give it a second try.

• Quick question for those of you who want to understand the cloth room better.
Where exactly are you getting confused and how? I want to make things simple for everyone, but that means making a lot of assumptions about what people know about Poser, and the Cloth Room. Since advanced and power users pretty much know what they're doing at this point, I'm assuming the people reading this tutorial will be mostly new Poser users and people who've only glanced in the Cloth Room's direction before.

• @eclark1849
To avoid making assumptions about pre-knowledge best separate fundamentals of soft body/cloth simulation and implementation of this technique in Poser.
There are a number of cloth simulators around: Marvelous Designer, Virtual World Dynamics, Blender, the DAZ system I forgot the name of, and I bet applications like Maya and 3DS have them also. A part of your audience may therefore be new to Poser but have their tracks in cloth simulation elsewhere. They just want to know the specifics of the implementation. Others will need to build some basic understanding of the process first.

This will 'catch' questions relating to the mesh walling apart because it is not properly welded.

The main confusion I see with people is when the cloth 'falls through' their collision object. They usually do not understand how collision is calculated; why, if you want to hang say a piece of cloth over a horizontal rod, it makes sense to have only the top of the rod act as collision object, and why the vertex distance of the cloth must be only a fraction of the diameter of the rod to ensure there is a cloth vertex colliding with the object polygon.
Problems with cloth hooking up on or falling through fingers, ears, toes and such have that same origin.

• @F_Verbaas That's needlessly complicating things and the very thing I want to avoid. They don't need to know how Blender, DAZ, or MD work. They need to know what to do to get Poser to work for them and work correctly.

• @eclark1849
It is your call. They all work on the same principle.

• @F_Verbaas I understand your point. I'm trying to keep this as uncomplicated as I can. They don't need to know how every other cloth simulator works, just what they need to do to get Poser to work. I'm reading some past threads from people about the Cloth Room right now, and one of the biggest complaints i see is that it's too technical to understand, and that the Reference Manual reads like a technical journal, which, to be honest, it does.
I was reading the manual's explanation for Shear Resistance, and honest to god, I think their explanation confused me even more.

• Did you know?

That Poser has changed the file format on dynamic hair and dynamic clothing? I rarely buy dynamic clothes because I can so easily make them myself, so when I save them to the library, it's usually as a prop. So as I'm reading the reference manual for the Poser 11 Cloth Room, I see this:

"Beginning with Poser 11 and Poser Pro 11, hair and cloth dynamic files are saved with an .abc extension (Alembic format)."

If this goes like in the past, this will be mostly ignored, particularly by the stores and vendors.

Stores and vendors can, in fact, safely ignore this change. The impact is on the dynamics file that's created when you run a simulation: it used to be .DYN, now it's .ABC. If you open a scene that was created in an earlier version in Poser 11, the simulation results won't be retained and you'll have to re-simulate.

• I'm doing a quick test right now on PhilC's Cloth Presets, and I'm having a bit of an issue. I've known about these presets for quite awhile, but I've never used them myself. Anyway, so far as how to use them, if you follow the instructions, they do what they're supposed to, and the numbers are entered in the fields they belong in. However, when I attempt drape the cloth over Andy, the draping dialog window appears, but it just sits there until i finally cancel it. On the other hand , if I change the numbers in the fields manually, the draping will begin almost immediately.

Just wondering if anyone else might have had an issue with Phil's Cloth Presets recently? Maybe it's a Poser 11 issue? Maybe my laptop is just crap?

• Quick question for those of you who want to understand the cloth room better.
Where exactly are you getting confused and how?

About how to pin object parts, about different types of body dynamics for making mixed material sims. About running multiple sims simultaneously. About they three or four types of collisions, and now, why according to verbaas, it would only make sense to define the top of a stick as a collision object.

Also, why, when I set self collision, the cloth still passes through itself when I collapse it to the floor.

• Quick question for those of you who want to understand the cloth room better.
Where exactly are you getting confused and how?

About how to pin object parts, about different types of body dynamics for making mixed material sims. About running multiple sims simultaneously. About they three or four types of collisions, and now, why according to verbaas, it would only make sense to define the top of a stick as a collision object.

Also, why, when I set self collision, the cloth still passes through itself when I collapse it to the floor.

a. You can't "pin" objects in the Cloth Room, but you can constrain them.
b. There are four dynamic cloth groups created when you start a sim. It's up to you to correctly identify them and place them into the correct group.
c. Yes, you can run several sims simultaneously, but doing so will tax your system and slow your computer down.
d. You need to ask Fverbaas why he said that.

• @eclark1849
@matb
Re a: Vertices of the 'choreographed' group move witht he transformations (scale, translation, rotation) of the cloth object. This effect is I think what @matb refer to as 'pinned'.
Re b: Only dynamic groups play a role in the simulaion. There can be multiple dynamic groups, for example for representing areas in the clothing that have different mechanical properties. I usually make a separate group for (shoulder) straps in which I set the tension resistance to a high level so they will not strain too much. Also you can in curtains for example improve the hanging by making the lower hem a separate group with high mass, similar to a lead-bead string sewn in real curtains.
The dynamic groups are the only ones having parameter settings. The other groups have no parameter settings and so there needs to be only one group.
Re c: AFAIK the sims can be run only one after the other. Usually one runs the sims from the collision object outwards, so first the shirt, then the coat.
Re. d: This has to do with how collision detection algorithms work. In short: collision objects need to be defined with the normals facing outwards. A cloth vertex found on the 'wrong' side of an object facet can then in the next sim step be sent back to where it belongs.
If the collsion object is double faced, or like in a rod there is a surface facing the opposite way nearby, the cloth vertex will get 'instructions' from both object facets, sending the cloth vertex in opposite directions. if the 'wrong' instruction is more pressing, the cloth vertex is sent in the wrong direction.