Scene file prep when using Renderman

The Renderman render engine has a few odd quirks we’ve noticed that are particular to how it operates in a render farm.  It’s important to configure your scene file correctly prior to submission, or these quirks will result in either no output or undesirable output.

Converting textures to .tex

Prior to submitting a scene file that uses Renderman as the render engine, you will likely want to convert your textures to .tex files.  If you try to make use of the default function to have those converted at render time, each render node here will try to run the conversion simultaneously.  This will result in access violation errors when multiple machines try to write to the same file(s).  Therefore, convert your textures to .tex files first, and disable the auto-conversion.  Converted texture files will still need to be pointed to using relative pathing, just like all other asset files.

Output path definitions

When defining a subdirectory structure in which Renderman writes its output files, this behaves as expected when rendering from a Maya GUI instance.  The subdirectories are created before output files are written to them, so Renderman won’t have any problems during the final phase of rendering.  In contrast, neither Maya nor Renderman will create those subdirectories when a render is run via a Maya command line instance.  Since this is how render farms generally run, the subdirectory structure will not be present on the farm when Renderman attempts to write output to it.  Renderman is not smart enough to create the directory structure if it does not exist, so writing the output fails.  The only fix for this behavior is to make sure that your output file definitions in Renderman are all set to the base output file path, not a subdirectory of the base output file path.  Then, when our Maya instances are told (via command line switches) what the base output file path for your job should be, it will exist when Renderman tries to write the output files to that location.

Renderman versions prior to 21

Pixar created some backwards incompatibilities when it released Renderman 21.  As a result, scene files created with versions prior to 21 will not render as expected in versions 21 and up.  Please consult Renderman documentation to see the changes and steps necessary to upgrade your scene file.

 

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