Iray Section Plane Node deleting pixels in hair entirely

mmdestiny

Note sure what to make of this one.  See attached image.  Oddly enough, the reflection of the hair in the glass behind her (not pictured) appears fully intact.

crosswind

Where did you place the section plane ?

mmdestiny

Parented and zeroed to the camera, then offset forward just enough for the offending walls to be masked enough for the full render frame.  Done that plenty of times before and never experienced this.  Only thing I can think of is the glass behind the figure is causing some draw order confusion or something. 

mmdestiny

@crosswind It's one of those WindField hairs that have some extremely thin cylindrical geometric hair mixed in with the alpha planes.  It was these thin cylinders that were blowing up the render.  If I hid them, everything was fine.  These same hairs on WindField's hairs can often cause extremely bright artifacting in normal renders unless you turn off their translucensy, so it's clear there's something bad-practice about those cylindrical hairs that causes issues.  Whatever it is, turning off tranlucensy wasn't enough in this case, so I had to turn them off completely.