View Full Version : LW/Bullet Cloth/Hair Dynamics Help DEPOT

06-20-2013, 01:52 PM
Hello dear community

I will have to produce a really massive amount of hi-quality cloth/hair simulation for characters for a personal film project.
Once it's too much work for a ONE GUY, it would help me a lot if I found the good tutorials, tips and samples at the same place.

Promisse to mention your help if I survive to this process.

So, if you have some good samples files to share and tutorials, please post it here and it will help me and others.

Also share the problems you find. This will help us to avoid some ways.

My Key problems are:

1) How to FIX a cloth area with a weightmap
2) Nice preset values for realistic character t-shirt and dress
3) Save extreme time consumption calculations
4) Nice hair ballance with aceptable colissions

06-20-2013, 01:57 PM
I will start posting the Greenlaw nice samples here:


A question? Is there a weightmap on SHAPE RETENTION ( T ) ? What is there?

Here additive cool tips from Greenlaw from other Thread

I'm using FiberMesh for Sister's long hair with Bullet and simple parenting works great--it should work the same way with Strand Modeler guides. You'll want to add a collision for the head of course, and possibly for the shoulders, as shown in that early Sister test (http://www.youtube.com/watch?v=jASC8IOsIqY) I posted several months ago.

If precise deformations to the hair root is important, you can use DP's Meta Fit node to attach the guides to the mesh. It's fine for human hair but can be a little slow for full body fur--in this case, it's better to weight the fur and then use 'Use Bones From' to reference the character's original skeleton. For ZBrush FiberMesh you'll need to use DrainBGVMap to transfer the character mesh's weight maps to the guides for this to work, but FiberFX Strand Modeler guides should already have the required weight map created when you clicked the Okay button.

06-20-2013, 05:05 PM
Agreed.The technology is surely there in LW but it's a bit of a mystery how best to set up fundamental things like dynamic cloth for characters and hair. Any good step by step tutorials out there? Thanks for setting up this thread Silvio :)

06-20-2013, 07:43 PM
Here's a tutorial that seems to cover some of the basics you'd need:


For your point 3) I'd say the biggest area of savings is to always use a basic collision object for your simulation and another object for the rendered character. Then for clothing in general always use a cloth object at the resolution for the amount of folding detail you want. And then another object that has the same resolution but has other details like pockets, buttons, seams and any other stuff. The simulated cloth would then drive the more detailed one with meta link which would require saving out the sim as an mdd and bringing it in to something like softbody to run it so you can link it with metalink.

For point 1) I don't know how that works in Bullet. But based on the above tutorial you could always parent some kinematic objects to a bone.

I would also consider using a 3D scultping/painting app to paint in grey scale values for attributes assuming the T includes an image map. But I have not used it so this is just a guess.

Image from a tutorial I did a while back showing a simple collision object for a character:

06-21-2013, 03:23 PM
Links for additional information:



Just remember that Cloth is a workflow as much as anything. Knowing how to set up cloth simulations is the Key. And that goes beyond the tool.

06-21-2013, 04:35 PM
What a frustrating day playing with Bullet. And the lack of documentation doesn't help.

My problem is simple, I'm trying to animate the rolled surround of a loudspeaker, you know, the bit that joins the cone to the chassis. I've got the cone driven by the audio track motion modifier, and set as a static object, (though I tried other settings as well), the surround as a separate object, using a weight map to hold the non-moving side fixed to the chassis.

First problem, I can't find any way to fix the other side to the moving cone. I tried nulls, parenting, and bones, no luck.

So, I put that to one side in the hope that the collision detection might work to just push the surround around. That works to an extent, but the deforming object either just tears apart or just gives hugely unrealistic exaggerated bumps and ripples. If I tune the settings to prevent this, it no longer moves with the cone, Now, after my last experience of Bullet, the first thing I did was play with the scale of the objects. Starting from real world 15" diameter, I took it right up to 7m with no real difference. Did all the other stuff too, like playing with simulation time frame, (took it up to 1200), with no joy. I'm beginning to feel that Bullet should be renamed Butterfly, the tiniest change leads to a hurricane as a result!

Oh well, tomorrow ClothFX beckons... :)

06-21-2013, 06:48 PM
For something like that I think I'd just use a bone at the center and control the deformation with a weight map. Move the bone with the motion modifier. From there just a matter of getting the right weight values for the effect.

06-22-2013, 02:49 AM
Thanks Richard. Whilst lying in bed last night I had an idea to use the loudspeaker model in an Estings (http://forums.newtek.com/showthread.php?136027-E4-esting-Competion-Entry) entry, which will need Bullet for other items, so I'm going to have another play today using the old cloth tools, (as you can't group forces in Bullet yet). Or I might try a morph map. I'll post updates later. ;)

06-25-2013, 03:04 AM
Thanks Richard!

Althought LW 11.5 Content have several cool samples of Bullet Cloth simulation, I did not get good results.
The reason is that the tutorials covers parts of a cloth and I need to simulate a complete cloth.

I'm getting results very similar to these onse from raymation3d


06-25-2013, 05:15 AM
Unfortunately I have not had a chance to play with Bullet cloth, so I can not comment on the specific settings. But as far as workflow I would suggest breaking up the garments into parts. In other words don't design a one piece garment. But if you do, make sure and have anchor points for that garment at the waist, neck and possibly upper arms.

For example this piece here:


Or if it is a modern fashion piece such as this:



Basically try to design your cloth to help solve simulation problems.

06-25-2013, 08:21 AM
As stated, Bullet isn't the best tool yet for Cloth.
You need workarounds to mke it work best.
At the moment, you cannot define different settings on the same object or make groups to ease the calculation.

06-27-2013, 06:22 AM
This is true. It is a very basic implementation. But it does however appear to have the option to map settings. Usually you can not have different settings on different parts of the cloth other than with maps which you can also do in LightWave classic cloth.

If self collision actually works, then it is better than classic cloth. If not then unless you want it to interact with Bullet you may not need to use it.

The main thing that it seems to be missing is the ability to control cloth getting trapped. Something you can do with nCloth. And also a few other features that would be nice for character cloth. But by and large you solve cloth problems in production with good planning. No cloth solution is full proof and will survive lousy set up. That is 95 percent of the problem. Which is why I provided those links to classic cloth set ups. It is all basically the same. What happens is people try to solve bad set ups with adjusting parameters.

Another very important factor is the quality setting on simulations. Another wrong approach is to assume you can leave quality settings for last. This can lead to the same issue where you adjust parameters endlessly when what is needed is a more accurate solve.