NURBS curves

[mattsmith]

Hi guys,
Can't find any documentation on rendering NURBS curves and I can't seem to get them rendering correctly. I've used both the Vray attribute on the shape node and going through the create-> V-Ray renderable curve. Same results either way which I've attached an image of. The tessellation has random missing faces and the rgb ramp I've piped in via a tube shader (surface shader results in obects failing to render) is only outputting red. Does Vray support the U and V coords of NURBS curves?

I'm running maya2014 ext SP 1, vray 24501 under linux.

cheers!

Matt

[ivaylo.ivanov]

These curves are actually rendered as hair. And it's somewhat normal to hit issues with bigger thikness and more complicated shaders. If you want quality and robustness, you should probably go with real geometry.

[mattsmith]

Thanks Ivaylo,
I've tried using a VrayMtlHair and the result is the same. It's just a 2D ramp node piped into the diffuse color, nothing complex, but the shader is only displaying red. Is it possible to confirm this as either a bug or user error? if it's user error, what's the correct way to set this up? Currently it's 2Dramp(Vramp) -> VrayHairMtl.diffuseColor -> VrayRenderableCurve.material

We use NURBS curves a fair bit for effects (motion trails). We can rebuild our fx tools to create some geometry, rather than output a NURBS curve, I just don't want to say to our FX TD "Vray doesn't really support renderable curves" if I don't have to

Best Regards,

Matt

[t.petrov]

In order to get this to work you should connect a VRayHairSampler in your Ramp node.
The connection should look like this: VRayHairSampler.distanceAlongStrand->ramp.uCoord
This will work for a U ramp, for V-ramp you have to use vCoord.

[vlado]

The missing chunks are actually fixed in the 3.0 builds, I believe...

Best regards,
Vlado

[mattsmith]

Fantastic, thanks guys!

matt

P.S. 3.0 isn't something we should be/are allowed to use in production though right?