I'm using Maya 8.5 and I have a problem with MR dielectric shader I guess. I imported mesh sequence from Realflow (v.4.0.0.0086) and assigned dielectric shader, added one light and HDRI map for reflections and refractions. In render globals refraction number is 10, reflection number is 3, Max trace depth is 20... everthing works fine, but for some reason after 118 frames all refractions just disappear (?!). Nothing was animated except mesh sequence (by default). Frame resolution was 720x576...
I made a new scene with the same mesh sequence but with othe HDR map and new lights as well. Same thing happened only this time after 54 frames (but resolution was 1440x1115). Strange thing is that refractions disappear in one part of a frame ( WaterSplash.54_lowres.jpg (http://forums.cgsociety.org/attachment.php?attachmentid=123031&stc=1) - you can see in the upper part of image couple of "blocks" without refractions) and from that frame on they are completely gone.
Is this problem related to dielectric material?
Does anyone have a clue where is the source of this problem?