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Specifies the rendering engine to use for rendering. The available options are the 'Path Tracer' (default) for the ray tracing based algorithm and the 'REYES' based algorithm. A discussion of Refer to the Pros and Cons of each is presented in the last section of this pageof Path Tracing vs REYES for a discussion of the advantages of each options.
Progressive Refinement
This option is only available when using the 'Path Tracer' Render Engine. When this toggle is turned on, the rendering rapidly shows a coarse image and refines it progressively until completed. This option is effective only for images outputted directly to a window on screen (i.e. to the Maya Render View or to 3Delight i-Display). During batch rendering (i.e. when using Maya Batch) this option is ignored. Note that this is not required when rendering in Maya IPR, which is progressive by nature and support dynamic edits of materials, lights and cameras.
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