Iray uber base displacement maps

genejoke

Hi, I've only recently started playing with Iray and have been trying to create a grass shader using displacement maps like I would in 3delight by increasing the tiling. However the subD thing limits its effectiveness on larger scales. Is there are way to this or is it a limitation of how Iray works?

Leana

Displacement is vertex-based in iray, so you need a really dense mesh if you want very fine displacement.

genejoke

Ah that's what I feared. Ah well there are ways around that. At least I know which angle not to pursue.

Hera

Is there a way to create similar altitude changes?

 

JonnyRay

Hera said:

Is there a way to create similar altitude changes?U

Unfortunately no. Both bump and normal maps simulate the effect of changes in the surface by changing the angle of the surface normal, but only displacement actually moves the geometry of the surface.

One of the reasons that displacement works so well in 3Delight is that behind the scenes 3Delight subdivides surfaces automatically when displacement is used. Iray doesn't. You'll either need to have a dense model to begin with or create the model to support SubD within Studio and use that feature to add enough additional vertices for displacement to look correct.