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Cannot open renderer description file "rmanRendererrendermanRenderer.xml"

You can copy the files from the RenderMan for Maya installation,

eg. C:/Program Files/Pixar/RenderManForMaya-2122.0-maya2016/etc/rmanRendererrendermanRenderer.xml

Into the directory where Maya looks for these under the Maya installation,

eg. C:/Program Files/Autodesk/Maya2016Maya2018/bin/rendererDesc/

Or you can set up the Maya environment variable called MAYA_RENDER_DESC_PATH so that rmanRenderer.xml and ribRenderer.xml will be found.

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