Iray and displacement

felis

I wonder if there is something I have overlooked or misunderstood related to Iray and displacement.

When it came out I bought "Heat Up for Genesis 3 Female(s) and Genesis 2 Female(s)" and "Heat Up Outfit Textures". The additional textures have both 3Delight and Iray materiel presets. One of the preset is a skirt with a zipper, which I did a test render on. The zipper came out flat, and when I looked in the surface pane I noticed that there was no map in displacement. I then compared it to the 3Delight preset which had the displacement map.

And it seemed to be the case for all the Iray presets - no displacement maps - while there were displacement maps in the 3Delight presets.

I considered it a simple bug from the vendor, and even though it is rather quick to add the displacement map, I filed a bug report so it could be fixed. My evaluation was that it should be fairly easy to validate.

But I have had quite some correspondance, which make me consider if there is something I have overlooked.

SpottedKitty

Do the Iray materials have a Bump or Normal setting instead? Displacement doesn't work quite the same in Iray as it does in 3Delight — what we're used to is actually an automatic feature that subdivides the mesh until the Displacement map can be applied properly. Iray doesn't have that, so if the mesh isn't dense enough, either it must be subdivided manually, or the Displacement won't look right and really ought to be changed to Bump or Normals.

I've already been bitten a few times by this in attempting to set up converted Iray materials; some objects just don't have a dense mesh, and if I set the manual subdivision too high, D|S might crash.

Steven-V

I second SK's comment, you probably want to use bump or normal maps instead of displacement. It's a bit troubling that an object that came with Iray mats did not do this for you, though. 

AndyS

Hm, the main problem is, that bump produces a good visual effect of the surface structures for light and shadow. But if you really want to have the 3-dimentional details, there is no use.

One example is shown in the attached picture. With iRay there isn't any chance to reproduce it.
Except: you build the structure of the tire with such a dense division's net to suit the necessary displacement resolution. But then your render will take some years.