Hair and Fur

[JustaTest]

Does anyone know if SL will permit us to import hair and fur ingame? Meaning, hair/fur that moves according to the wind, gravity, etc. much like a flexiprim works.

[Feynt Mistral]

Depends on the hair.  It will most certainly not be flexible in the beginning, but they may allow us to apply "flex maps" at some point which could be greyscale textures allowing avatar physics like motion (i.e. not affecting the sim, completely server side).  Rendered hair and fur like what Maya or the new Blender hair/fur system will not be importable.  Low poly hair like this however:

http://www.cgarena.com/freestuff/tutorials/maya/lowpolyHair/index.html

Will certainly be allowed (provided you spend the extra polys on the other side of the hair, since we don't get double sided polys for free right now.  *HINT* *HINT* *nudges LL with a clue by four*  )

[Ashasekayi Ra]

It's doubtful. They have already stated that they won't be creating "flexi" mesh. I suppose the only thing that might give the illusion of hair movement would be a custom skeleton and animation support, which they said they would possibly add in the future.

[Feynt Mistral]

Definitely doubtful that it would be made flexi, because determining where the root of the flexing should be is likely to produce odd results, but I think I can come up with a system that would work using greyscale maps.

[Nalates Urriah]

In the group meetings this has been discussed several times. The Lindens are NOT looking to add 'flexi' to mesh.

However, they are looking at other ways to get the same result. Using mesh to build cloth and hair with movement is some where on their roadmap. I doubt we'll see much work on it until mesh is working well.

[Ashasekayi Ra]

That would be pretty cool Feynt. How exactly would the maps make the mesh move? Would this be something that would work after LL added code to support it?

[Feynt Mistral]

Yes it would need supporting code to work.  >D

 

The idea is basically that Qarl had suggested once about making sculpties flexible with an associated greyscale map controlling which parts of the object should bend along a particular axis (the same as other prims, most likely).  In this case there are a couple of ways to do it, but the one I would pick would be having black segments of an associated texture (matching the UV of the mesh object) count as rooted vertices.  Then all vertices connected to an appropriately encircled rooted area which are not black will be flexible along a flexiprim like bone structure rooted at the center of this ring of blackness that affects the vertices just on the edge of the greyscale change.  The whiter the UV area, the more it moves from its original position.  The idea is if you were to apply this texture as the object's UV map, every dangly part that's suppose to move would be various shades of grey or white, while the parts that shouldn't move will clearly be marked full black.  Programmatically it shouldn't be too hard to generate the root point, but identifying which vertices should flex how much with the flexi string would be more problematic.

[8Ball Helix]

Although it's not optimal I suspect what will happen in the meanwhile is that we'll see a mesh base plus flexi prims.

So in other words instead of having 100 sculpties plus 50 flexis we'll see a single mesh plus 50 flexis.

It'll still reduce lag significantly even if it lacks physics.

 

I wonder if soft body physics could to be made work with flexi prims. That would help at a minimum.

[Ashasekayi Ra]

Thanks for explaining that. It sounds very interesting. It would be nice if they added some kind of feature to allow some simple movement that doesn't require you to go in and make a rig every time.

[Feynt Mistral]

The other option, and probably more professional, is to accept additional bone data and then have modifiers on those bones which register them as "free".  This way it becomes a case of weight painting, and flexi-physics can take over on the bones.

 

Oh and another, if they implement morph targets, we could animate between the various states of our wiggly stuff and the appropriate extremes can be animated and blended together according to scriptable motion control (tying animation control and LSL together).  This would also allow us to create morph targets that match the default avatar, thus making support for the appearance sliders seamless if we choose as well as animateable mesh faces for talking.  But since morph targets are typically less popular than bones (at least in game design) this is not a likely option.

[Ashasekayi Ra]

Yea, I would love morph targets. But, the Lindens have vetoed that idea at the mesh meetings every time it has been brought up.

[Feynt Mistral]

Well, again, morph targets are unpopular for real time graphics where programatic control is done.  Bones can be directly manipulated in code and commonly are their own objects, while morph targets are typically just different animation states.  You can't really do much with morph targets in code.  For movies morph targets are grand since you can blend between animation states (blend angry facial poses with the phoneme sequence for "what the hell?!" for instance), but you can still use bones to do the same things.

[Ashasekayi Ra]

True. Bones would be the most appropriate place to put their limited coding cycles. Facial morphs are just easier to make than facial rigs. But, such is life.