Feedback Wanted: Cloth Improvement Plans

I love what Marvellous Designer does, but I assume for most games you need an extra baking phase to use the produce clothing assets? Designing in Marvellous is then analogous to sculpting a high poly version, after which you bake all the detailed creases to a retopologized version of the mesh.

That said, if you think something similar to Marvellous could be used to both author cloth content and simulate it at realtime with other things going on, go for it.

As for my specific use-case: I'd like to use simulated cloth in Volo Airsport, but due to the high velocities the characters have I have not been able to find a stable setup in the past.

 

hi @Tinus,
A comment regarding the Airsport cloth:
Have you experimented with scaling down the .worldVelocityScale or .worldAccelerationScale and use the .externalAcceleration to get the wind direction you want? You (should) just need enough force to inflate the "sails". In my mind you can then apply an ocean-ripple like vertex shader on the "sail" mesh to get the really fast moving turbulence.

 

I liked that the old cloth with the right pressure settings could be used as soft bodies. Any chance of bringing that functionality back?

 

I actually used cloth only a few times for testing. My impression was:
1. very huge performance impact
2. very vulnerable to fast rotations (then the cloth mesh was twisted and couldn't free itself anymore)
3. not much influence on it via code (don't know if that really matters, I'm a programmer, not an artist, so this was more for me to check what I can do with it via code).

My main target platform is mobile, so I guess cloth is not the feature I should use, but I wanted to share my experience with it.

 

My only comment would be on delivery, rather than a custom asset or special build, it should follow the UI pattern and be listed on OSS (as much as is feasible)

 

Absolutely, it was a nice component to experiment with. It might not be the best solution for (character) cloth, but it could be used very creatively.

 

Improve Performance!
As a goal,

 

Thank you for wanting to work more on the Cloth system.
I have a lot of things to mention here, and it's hard to know where to start, so I'm going to dive right in.

The most important feature that I would like to see added to the system is the possibility of driving a mesh with a simulated cloth. I see this as the single most important feature of any cloth system. The lack of such a feature forces us to write a lot of different wrap scripts and vertex-parent-constraint scripts to work around the issue.
You almost always want to have a simplified single-sided cloth mesh (unless you are simulating a sack, but that's not possible without self collision anyway), and you almost always want to have a more complex render mesh with thickness. We're now forced to use our own wrap system written in c# which I'm sure is not as optimized as something you could create over at Unity.

This leads us to the next issue, the fact that querying the vertices of the cloth in any of the available updates gives us the position of the vertices before they have been modified that frame. Which means that all deformers and constraints we write to drive things with the cloth mesh lags one frame behind.
And while on the topic of querying; being able to query the vertex normals instead of having to recalculate them on our own would be great.

Furthermore, the expected behaviour of stretching stiffness 0-1 and bending stiffness 0-1 would be: That on 0 it would be able to stretch in to infinty and bend in whatever way it want, and on 1 it would not stretch at all and not bend at all. That is currently not the case.
Having these two attributes as globals for the whole cloth system is also very limiting, it would help a lot if we could paint these on the cloth and therefore specify different settings on different parts of the cloth.

Box colliders would be appreciated.

Being able to specify a ground-plane would be appreciated and help alot, even though a box collider would serve the same purpose. We currently have to move a ginormous capsule collider around with the character to have the cloth collide with the ground when the character enters ragdoll.

Self collision would be very appreciated.

Having a visual representation of the length of MaxDistance and SurfacePenetration per vertex (and being able to toggle it on and off!) would help alot when designing cloth behaviour.

I think that's all for now. Thanks for listening.

 

Hi,

We use cloth on almost all our characters in our game so we have some feedback for you.

1. Non-allocating vertices queries
Quering vertices right now allocates a new array with vertices every frame, this triggers a lot of garbage collects. In 5.3 you add non-allocating physics queries which is great and that would be perfect for this case too.

2. Reset cloth method
It would be great with a Reset() method on cloth which resets it to it's default pose. Right now we have to disable it and then enable it the frame after.

3. Simulate cloth method
When pooling our characters there is a lot of deactivating and activating going on. When we active a character we set the correct state on it. Position, rotation and animation etc so it can be visible in the right state that frame. Right now we reset the cloth to it's default pose. That means the cloth wont be in it's relaxed state until a few frames later. What I propose is a method that will simulate the cloth and relax it for us in one frame. Much like what ParticleSystem.Simulate does. Maybe something like this: SimululateCloth(float solveCount).

4. Callback when cloth is finished solving
Like Gabriel(Cal0n) said when querying the vertices of the cloth it's always one frame behind because the cloth solves after LateUpdate. We use this to make a transform follow the surface of the cloth and it works good the problem is it's one frame behind (and it's allocating). If we had a callback like OnClothSolved or something we could use to move the transform it would help a lot.

Thanks for listening!

 

Can I get a re-initialize hook for when a skinned mesh gets vertexes updated at runtime?

Right now it keeps the old vertex list.

 

Hi Sean.
This is what I would expect such a wrap to do:

• The green plane is the cloth.
  
• The blue strange looking object is the driven mesh.
  
• The vertices of the blue object is smoothly transformed according to the vertices of the green object.

Ideally such a system would be setup by simply providing a target (driven) mesh to the cloth component without having to worry about fallof-settings, distance-thresholds etc.

 

I do not have much of a feedback to give since I haven't used the cloth component as much.
But I have encountered a problem which I'm not sure if it is a bug or this is how it should work and I made a thread here
http://forum.unity3d.com/threads/cloth-physics-constraints.368022/
If I remove the cloth component but keep the skinned mesh there is no performance issue, but disabling it acts the same way as if it was enabled.

 

Hello Sean,

My email address is info@mary-kyri.com
I was wondering if you could email me an email address where I can ask several questions about cloth. It is highly confidential and therefore I cannot post it here within the forum. Megan from support advised me to contact you, saying you were happy to answer some questions.
Thank you

 

Having access to the bone info would be handy, also being able to disable the skinnedmeshrenderer and still have the cloth running, I have done my own version of the wrap system mentioned above but cant use it since I have to have the cloth skinnedmeshrenderer running at the same time. Also if you exposed the bone info you are using for the skinned mesh that would save me having to duplicate and calculate it every frame as well.

 

Any update on performance improvements?

 

No, just wondering when these will be implemented.

 

How could i miss this thread ?
I think what the cloth system lack in unity right now is the authoring part, could be cool if we can author using third party tools ie nvidia cloth authoring tools (standalone or dcc) and unity cloth can import those settings, it could be better for artist workflow since they don't have to go back and forth switching apps when tweaking cloth.
Using proxy mesh cloth driver / Skin Wrap (3dsmax) like Cal0n describes is a great idea, especially if we don't require a high detailed cloth sim.
Oh and support for cloth interaction with external force could be great especially wind
is the garment maker really necessary? just curious. Since that usually hi-poly initial modelling phase.

Oh btw this is not specific to cloth system, but might be still connected.
Since you planning to adding brush system for in editor cloth authoring tool, i hope you guys creating a unified and extendable editor brush API which can also used in terrain, object placement, vegetation system, or maybe texture and vertex paint

 

I see, alright that should be no problem if you guys can do that. i'm hoping that unity have the same tools for authoring the cloth system. Would be pretty cool if we can isolate only the object that we want to edit.
Unity could gain advantage of somekind unified painting tools .
Can't wait to see what you guys gonna added to unity.
@yant just fyi arkano already have proxy cloth for obi tho. . . yes it is usefull,
forum.unity3d.com/threads/obi-cloth-bringing-old-cloth-back-to-unity-5.337322/page-4#post-2496760

 

A way to exclude vertices from the simulation would be great.
Related to that would be to have this bug fixed: http://answers.unity3d.com/questions/956610/excluding-vertices-from-cloth-colliders-in-unity-5.html
I submitted a bug report but it was denied saying it was a feature. @yant
I see cloth improvements in the roadmap, but nothing about a wrap/proxy/driver system. Any plans in the near future?

 

Hi,

Just wanted to tune in to this thread. I´m the lead developer of this: https://www.assetstore.unity3d.com/en/#!/content/81333

While not using Apex underneath (so we don´t know if certain things would be possible to do w/ Apex), we feel the way we expose many common cloth-related tools in the editor (such as per-vertex editing of cloth properties, generating mesh-mesh skinmap assets to transfer simulation from low-poly meshes to high poly ones, etc) are steps in the right direction.

Since we've already walked this road for quite some time, I think it would be beneficial for you to take a look at the result of our efforts and see which things work and which don't in terms of usability (there are quite a few rough spots in Obi that could probably be smoothed out with tighter integration in Unity). Hopefully this will help you guys figure out the best way to expose all of Apex's functionality in Unity.

cheers,

 

Any chance of making it possible to deform cloth? Such as rips/tears and holes in the cloth? This would be really cool if it was implemented natively within Unity.

 

Have you guys considered using NvCloth instead of Apex?

Seems to be lower level and though it probably does not support tearing (as it breaks constraint batching, hurting parallelism in the general case and also consumes more memory since you cannot instance constraints) it is certainly simpler and more flexible.

Could make your life simpler, that is.

 

Deformation would be a step in the right direction

 

is this implemented already? in 2018.x.
I know you guys have a close beta
(FYI : and no i'm not in close beta just in case you are wondering)

 

the version unity 2018.3.0 has upgrade physx from 3.3.3 to 3.4.2, which support NvCloth!