Short fur dynamics

 
 
 
Posted by:nottoshabi
Data created:19 December 2016

I'm re posting this from cgTalk.com so we can go into a little more detail.

     Im running Ornatrix 4 and I have added short fur on my character, styled it and combed it everything looks good. When I went to run the dynamix on the short hairs I can't get them to stop dancing and gittering. I have increased the damp to as high as 9000 and as low as 1.99 and still get the same effect. I have tried all of the presets and I get the same effect. The sub steps and solver iterations seem not have to much effect on the gitter besides making the sim longer. 

My scene is set to cm. I only have one character in the scne the one I'm working on. He is 229.784cm tall, the global hair lenght is 50.cm. and a little longer in some places do to combing. The amazing thing is that if I try doing the same hair set up on a sphere in a new scene the dynamics work straight out of the box. And they are as one would expect damping, spring, and swing limit do what they are supossed to do. So what am I doing wrong? I can not change the topology or height of the character or the style. 

 

I would really like some help or direction figurring this out. 

Hi Nottoshabi,

Is difficult to help you without taking a look into the scene. Have you tried doing the same test with a sphere in the same scene? did you get the same result?

Jeordanis Figuereo (Product Designer. EPHERE Inc.)

I definitely can not send you the scene or talk about the character. I have created a sphere added the fur ball preset to create hair, then after the Ox Hair from Guides, I added a strand detail, strand curling and strand clustering. Messed around with the settings a little bit so they wont be default added the dynamics modifier choosed the wet hair preset and it works just as you expect it. The only difference between the static sphere and my character is mine is a deforming geo being driven by point cache. The hairs are grown out of a duplicate of the character body. And broken up in pieces, arm, head, torso and so..... And that geo is skin wrapped to the deforming geo. Am I doing something wrong? Is moving the points around disturb Ornatrics way of setting up the hairs with dynamics?

I see, we should wait for Michael MCcarthy, he will be able to help you more than I.

Jeordanis Figuereo (Product Designer. EPHERE Inc.)

In the guides from surface I have remember root position turned on. I have been trying to fudge around with the settings for damping, spring and swing. But every number gives the same effect. So I changed the start segment to 4 turned off all strand collision. In the physical properties the settings that are on the modifier and the explanations on the docs do not make sense or match up. In the docs on this page this is what they say:

Physical Properties 

  • Global scale
    Not currently implemented
  • Mass
    Controls the mass/weight of every strand of hair.

So I'm assuming that the global scale does not work, so a value of .1 or a value of 10 will give the same results? Mass is the hair density? Meaning is it heavy like alpacka hair, or dense like porkiepine needles? Also how does it calculate, is it a multiplier or adition to what hair segments hair lenght? What gives it mas/density?

 

It is hard to say without a sample of your scene. I would guess that the issue has something to do with scene scale or wisp size. Maybe you can reproduce the issue on a simple scene and shoot it over? Or strip down your scene so there is no proprietary info in it.