Given a deformation on a NURBS Surface, my first suspicion would be a
triangle being squished to the point it has zero area. Mental ray doesn't
like triangles with zero area. Another way to trouble shoot is to change
the parameterization settings for rendering away from parametric and use
view dependent subdivision. This will force triangulation to be rendered
per the camera's point of view and perhaps give more granularity where
needed to avoid the problem.
In any event, Mental ray is pretty good at dumping information to reveal the
cause if you set it up to do so:
1) In your render settings, go to the mental ray "diagnostics" tab and
activate all the check boxes under "logged messages". This will put mental
ray in full verbose mode and dump everything it does to the script log.
This will also slow rendering down drastically, but the purpose here it so
find a problem, not make pretty pictures.
2) In your scripting preferences, activate "real-time message logging", and
"log to file" while also specifying the log filename. This will ensure
whatever mental ray logs will get stored in a file on your hard drive and
remain accessible in the event Softimage crashes.
3) render your image
4) inspect results of the script log. If you crash, open a windows explorer
and navigate to the script logfile and rename it to a new file name. You do
this because the moment you restart Softimage, Softimage will erase the
script log in preparation for the new session. Renaming the file before
restarting softimage ensures you still have the debug data from mental ray.
5) comb through the logged data and look for errors, usually labeled
'fatal'. The true error will always be one or more lines above the where
fatal error message appears.
I can help decipher the log if needed.
Matt
Date: Wed, 14 Oct 2015 15:27:11 +0100
From: Chris Marshall <[email protected]>
Subject: Mental Ray Fatal error
To: "[email protected]"
<[email protected]>
Hi All,
I have a nurbs object that's deformed with a lattice. I'm doing some shape
animation on the lattice, but when I render a sequence, I get a Mental Ray
fatal error after it completes rendering frame 1. I've remade the lattice
animation on a new lattice, but I get the same error. If I delete the
lattice, it renders ok. So it looks like an issue with nurbs/lattices/shape
animation. Is this a known problem? Any thoughts/workarounds?
Thanks
Chris
