mpng writes a series of numbered movie frames to png files with the specified prefix. If the ray_trace_frames variable is non-zero, these frames will be ray-traced. This operation can take several hours for a long movie.
Be sure to disable cache_frames when issuing this operation on a long movie (>100 frames) to avoid running out of memory.
mpng prefix [, first [, last]]
Options "first" and "last" can be used to specify an inclusive interval over which to render frames. Thus, you can write a smart Python program that will automatically distribute rendering over a cluster of workstations. If these options are left at zero, then the entire movie will be rendered.
cmd.mpng( string prefix, int first=0, int last=0 )