Some interesting iRay issue

ant2505

Hello, everyone!
I did a kind of transparent tube with stickers on it. For that i created two groups of surfaces: first - tube itself, second - surface for stickers on the tube. Tube has refraction weight =1, and stickers surface has it's own transparancy map. When i render in close distance to camera, everything looks fine, but when i increase the distance, stickers from the backside (in relation to the camera) disappear. I geuss it is cause of small distance between my two surface groups. Looks like the more distance from camera the harder it is for iray to pay atention to small distances and it catches it like two intersecting surfaces, perhaps. Kind of optimisation, i think. I managed to fix this issue using a geohell for the tube and leaving only stickers surface on it, while stickers surface on tube i make absolutely transparent (cutout opacity=0). My question is: is it the best way (in terms of render quality) to fix this kind of issue, or did i miss something?

Richard Haseltine

Yes, this is rouinding issues - it can affect anything with surfaces very close together. You coulsd try changing the Instance Optimisation setting (Render Settings - then change it back to the value you want) to force a reset of the origins.