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If the Animation toggle is on, specifies the range of frames to render (bounds are inclusive). The default range is [1..1].
Increment
Specifies the increment to use when going from one frame to the next in the frame range. For example, if the frame range is [1..6] and the increment is 2, only the following frames will be rendered: 1, 3, 5, 6 (note that the first and last frame are not skipped). The default increment is 1.
Skip Completed Frames
If the Animation toggle is on, turning on this option will check for all image layer files that must be output for a frame. If they all exist, the frame is skipped and 3Delight for Maya proceeds to the next frame. Note that the verification is done on the image layer files existence only, not their actual content. If all file output is disabled, this option is ignored.