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Note that checkpointing is designed for batch rendering to images on disk. Renders to a live framebuffer such as "it" are already updated on-the-fly as the render proceeds. Of the built-in display drivers, currently, only the TIFF and OpenEXR display drivers support checkpointing. The "Output Type" on the RenderMan LOP must be set to OpenEXR or TIFF rather than "Raster" to cause RenderMan's display drivers to be used. Even though Husk can render output OpenEXR or TIFF images in Raster mode, the RenderMan display drivers are not being used in that case, so checkpointing will not work. You may notice that the image files produced by RenderMan include a ~w labeled channel. This is data stored to resume a render from this file.

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