Hi,

I'm trying to write a surface shader to render a curve that looks 3D by basing the shading on the width in the L-System. However it renders fine in the ipr but when rendered out it is completely black but only renders the alpha.

Image here [dl.dropbox.com]

Any ideas?

Thanks.

Try connecting the BSDF.

If it don't help put up the file. Guessing without trying is not very effective.

Thanks for your help, I had tried for a couple of hours and it wasn't working at all. It's the first time I've really delved into the shader menu.

Connecting the BSDF didn't work, but I then changed the render type from micropoly (mantra default) to raytrace and now it works, the micropoly method can't agree with this shader I'm imagining.

Thanks for the help btw.

AFAIK, IPR use raytrace engine. BRDF in a shader is for PBR engine.
I think your problem is the color of points or primitives in your geometry.
Try to delete Cd attribute with an attribute SOP or set it white with a point SOP/primitive SOP.