Shells Turning My Actors Skin Black in Places?

RenderNovice

All,

I have a recurring -- yet intermittent -- issue when applying shells to my actors:  most often I see it with the "So Sad" (facial tears) shell, but it sometimes happens with other shells.  When I apply it, portions -- sometimes large protions -- of the actor's skin turns jet-black.  I have "Shell fix" scripts that come with other products that sometimes fixes the problem when applied to the offending shell -- but sometimes it doesn't work.  It rarely happens if I'm just building the character under dome lighting with no other elements in the scene.  When I merge that problem-free character into another scene however, portions of the skin again turn jet-black.  Translation: I am unable to isolate/identify what cause this to intermittently happen.  Re-applying the actor's skin materials does not seem to fix the problem.

Any help would be appreciated -- I can't be the only one seeing this!  

Richard Haseltine

Try changing the Instancing Optimisation setting in Render Settings - that forces Iray to recentre the scene, which often deals with the issue.

RenderNovice

Thank you Richard -- that resolved it.  "Speed" or "Memory" Instancing Optimization eliminates the problem.  Returning to "Auto" brings it back.  I'd have NEVER figured that out on my own . . .