Hairtrix export to Vray primitives beta test

[ikolev]

Ivan- is there any more info on hairtrix?
I can see the plugin for sale on turbosquid but there are no actual website with info anywhere!

Providing info about the product is up to the publisher, Turbo Squid. The info about Hairtrix is just the same as it was for the predecessor, hairfx, which I agree is not very much. I'm not sure what is their policy of providing demos, but I think they do provide demos to any serious users. The only detail is that you should contact them either by phone or through the support system on their website, not by e-mail - their spam filter is too harsh.

As for hair and GI - I can't tell how useful it can be to compose non-GI hair over a GI-character. If we assume that it can be useful, then the built-in renderers in Hairtrix can do the best non-GI-hair-rendering job you can find anywhere.
If we assume that we absolutely need GI for hair, then you won't find a hair-modeling product which includes a GI renderer, because that's a huge task which takes a separate product, such as V-Ray. That's why we have decided not to develop the renderers built in Hairtrix further, but to look for integration with established renderers. So far our experience with that has been poor. No renderer we've tried provides useful GI rendering of hair (we haven't tried Renderman). We are ready to do our best to convert Hairtrix hair to any external renderer, once the renderer has developed a well-established API or interchange format and proved that it can produce decent results. mental ray provides a solid and simple API for hair import, that's why it is easy to write exporters to it. But as I said, we haven't yet seen any decent results produced neither with MR, nor with any other GI renderer.

[rajdarge]

shame that haitrix has stalled. It seemed to hold a lot of promise. I've used max hair (shave and haircut) in geometry mode and its damn slow and the hair looks like wire. Nothing else seems to work. Vray fur has only recently had a tapered option, but it too looks too solid to represent hair it requires a lot of work with a paintbrush to fix it. Those test renders looked great, the hair was a little thin for grass and but a cool effect none-the less. How does the styling interface work? I liked the one in max hair, but doing multipass renders between 2 different rendering engines with different materials is a PITA.
Raj

[Davy]

so far the better hair solution I have ever worked with...
http://www.chaosgroup.com/forums/vbu...ad.php?t=40310

looks like I can get proper GI and shadows underneath my hair with a vraysun...
and I am finally giving my characters proper hair in 1 pass without complicated methods...

looks like a very good solution compared to the hair of max which is useless (in my testings)...try to render animations with max hair and your shadows will flicker hurting your eyes and you need multiple light sources composing shadows and what not

davy

[joconnell]

Renderman gets an easy time of it since it uses so much lazy loading where geometry is only loaded in when it's need to render a bucket and then it drops immediately afterwards. Also of major note is the fact that if you want to get this really fast pace from renderman then you can't do any kind of raytracing. As soon as you do that then the geometry in one bucket might reflect something in another bucket which is where all of the speed and memory advantages die off. If you had lots of raytraced shadows on hair or GI then you could have rays that end up bouncing over nearly every portion of the screen so you'd need to have the lot loaded into memory to calculate. It's the same reason the hair FX buffered render is so quick - it's not doing any complex raytracing or interaction with all the other objects in the scene so it doesn't have to obey the same rendering rules. Admittedly you lose the convenience of one lighting setup working across everything and having a solid connection between hair and source object but you gain back in the speed.

[ikolev]

looks like I can get proper GI and shadows underneath my hair with a vraysun...
and I am finally giving my characters proper hair in 1 pass without complicated methods...

So, you mean that this vraysun light casts proper GI illumination on hair, and casts shadows? That's good. Which environment renderer did you use? (there are three of them, one provided by hairfx and two by Ornatrix)

Actually, finalRender has a simple approach to GI for such "externally rendered" objects like hair - it provides two special lights, one for GI and one for caustics (I think), which simulate the GI illumination in a specified point when asked to. So the hairfx renderer gets access to these lights and receives *some* GI illumination, probably not perfect as it would be when calculated strand by strand using geometry, but fast and enough for most cases.

[vlado]

Ivan, the same goes for V-Ray - V-Ray provides a "GI light" that, when called, handles global illumination and caustics. This is used, for example, to make standard materials work with GI. It is not the most efficient thing in the world as some optimizations cannot be applied in this case, but it works.

Best regards,
Vlado

[Davy]

So, you mean that this vraysun light casts proper GI illumination on hair, and casts shadows? That's good. Which environment renderer did you use? (there are three of them, one provided by hairfx and two by Ornatrix)

yes and no
it casts proper shadows and it produces GI underneath your hair,
it does not produce GI on the hair itself,

but all the rest works and I am in the middle of a bigger scene to test it more throughout

its not perfect yet (since you still need an omni to lit the hair because of a bug and hair itself doesnt have GI which I don't care for) but I am very pleased so far...
and for sure its the better solution I have worked with to date...

davy

ps. oww yeah, I used 2 engines, one fast and the other accurate

[ikolev]

Ivan, the same goes for V-Ray - V-Ray provides a "GI light" that, when called, handles global illumination and caustics. This is used, for example, to make standard materials work with GI. It is not the most efficient thing in the world as some optimizations cannot be applied in this case, but it works.

Great. Does the material (or atmospheric) have to do something special to support these lights (as it was with finalRender), or they are just present in the list of current lights provided by the renderer, so they get automatically enumerated and used by the material/atmospheric? I get the feeling that it is automatic, since you say that it works for standard materials.

Regards,
Ivan

(sorry for the late reply, I just found the option for e-mail notification about the thread)

[vlado]

It is automatically provided by the renderer, yes. There is nothing special needed from plugins to get access to the GI light.

Best regards,
Vlado

[ngrava]

Wait... What happend to this? Ivan, did you get anywhere with it? We do a ton of Fur rendering all the time... We need GI with Fur more then anything else. Cantact me! Please!

Galen Beals
Bent Image Lab

[ikolev]

Wait... What happend to this? Ivan, did you get anywhere with it?

If you're talking about export of hairfx/furfx to Vray hair primitives, it was going well until I had the time for it. With the help of Torgeir Holm as a tester I was able to fix several bugs and bring performance up to that of tri-mesh export. Torgeir reported that a scene which took about 700 additional MB for the tri-mesh hair now takes about 100 MB with primitives export and renders about as fast. However, primitives export doesn't work with 3D motion blur yet, and UV coordinates export is fixed to constant UV for the whole strand. So there's still work to do, but unfortunately I don't have the time for it right now. I hope I'll find some time within a month.

[wxyz]

finally got through to Turbosquid and upgraded to Hairtrix. Do you need any more beta testers? mY INITIAL EXPERIMENTS With the latest build were promising.

[ikolev]

hairfx->Vray export is now in my top priorities, but recently I ran into a quite nasty problem with the hairfx shader (it's related to Max, not Vray), which I can't solve. It is what stops me from publishing an initial version of this feature (which for now will not support 3D mblur for deforming hair).

[wxyz]

Max 2010

is an update for Max 2010 available?