Reuse depth maps

If you use depth map shadows, by default Maya calculates at least one depth map for each depth-map enabled light source and for each frame of the animation during rendering.

In some cases, you can reduce rendering times by saving and reusing a light’s depth map. See the following table to determine if reusing a depth map is advantageous for your particular circumstance.

Maya saves depth map files in the renderDate/depth directory of the current project, by default.

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Rendering a single frame several times, each time making adjustments to object or light properties, but not moving lights or objects, the depth map does not change and can be reused.	Set Disk Based Dmaps to Reuse Existing Dmap(s). Maya calculates the depth map the first time you render and save it to disk. During each subsequent render, Maya reads the depth map from disk.
Rendering an animation in which the light or the objects it illuminates do not move (for example, a camera fly-through), the depth map does not change from frame to frame and can be reused.	Set Disk Based Dmaps to Reuse Existing Dmap(s) and turn off Dmap Frame Ext. Maya calculates the depth map when it renders the first frame and save it to disk. During each subsequent frame render, Maya reads the depth map from disk.
Rendering an animation in which lights and, or the objects they illuminate do move, the depth map changes from frame to frame. If you are rendering the entire animation several times, each time making adjustments to object or light properties, but not changing the way lights or objects move, the depth maps for each frame is the same as in the initial render and can be reused.	Set Disk Based Dmaps to Reuse Existing Dmap(s) and turn on Dmap Frame Ext. Maya calculates the depth maps for each frame the first time you render the animation and save them to disk. During each subsequent render, Maya reads the depth maps from disk.
Rendering a single frame or an animation, have previously saved depth maps to disk, and have moved lights and, or the objects it illuminates, the depth maps are now different, and you cannot reuse the depth masks on disk.	Set Disk Based Dmaps to Overwrite Existing Dmap(s). Render the frame or animation once. Maya calculates the depth map(s) and save them disk, overwriting any depth map(s) that already exist on disk.If you want to continue adjusting object or light properties, but not move lights or objects, set Disk Based Dmaps to Reuse Existing Dmap(s).
Rendering a single frame or an animation, have previously saved depth maps to disk, but do not want to use the depth maps that are on disk.	Set Disk Based Dmaps to Off. Maya calculates the depth map(s) every time you render. Maya does not read depth maps from disk. Maya does not save depth maps to disk.