ptex for dummies!

[cdavis]

could anyone describe the workflow on using ptex, i cant work it out?

just trying from mudbox to maya/vray, no joy so far.

Thanks

[bernhard]

good point.. would love to see one simple example as well ! thx for posting !

[irobert]

For basic maps, color, spec ect, ptex seems to work okay for me sometimes. Make sure you have your ptex ready mesh in Maya, at lvl 0, then use the vray ptex node for vray to plug into the vray mat. I can't get it working with displacement though.

[Metzger]

I haven't tried the ptex in Mudbox, but I can tell you that the Mari Ptex is really sweet and very well done. Just make sure you pay attention to what resolution is being applied to each face. You can very easily overdo things. The other thing you want to make sure is that Mudbox saves mipmap verions of the ptex so Vray doesn't have to load the highest resolution. I did a sphere test painting on a 4k poly face and the ptex file was only 4k. It has really killer compression in the file format.

One thing to note is that you will want to either decide if you are going to subdivide. Currently you can use Vray Sub-Ds and the ptex will subdivide fine, but you can't paint on a low res model, then put a maya smooth on it. I haven't tested it out that far. Now eventually there will be more support to copy ptex from model to model where you are changing the geometry. It would be nice to have a ptex bake function for vray so you could take UV textures and convert them to a ptex file. I think renderman has some command line tools, but I am not 100 percent sure.

[vlado]

It is fairly simple, from my tests - just export your PTex files and use the VRayPTex texture to bring them into Maya. As Scott mentioned, the PTex files are exported for a particular topology of the mesh, so you must make sure it matches between Mudbox and Maya. You can use the V-Ray subdivision attributes to smooth the mesh.

Best regards,
Vlado

[irobert]

Is displacement working?

[vlado]

It worked fine when I tested it. Vector displacement might be a bit tricky, but regular displacement was generally fine.

Best regards,
Vlado

[irobert]

Thanks, must be user error, I will have to give it another try!

[VasilVelikov]

Actually, it wasn't a user error. I just found out that there really is a problem with the displacement caused by some recent changes. I'm working on it now.

Best regards,
Vasil Velikov