Recycling rendered images to save time

User Guide > Rendering and Render Setup > Rendering > Visualize and render images > Visualize scenes and render images > Work with render layers >

If you have a Maya scene with more than one render layer, you can recycle the rendered image for the layers that are done. This saves rendering time by eliminating the need to re-render layers that you can reuse.

You can use this feature in one of the following scenarios:

If, for example, you have five layers in your scene, and 4 of them are fine but 1 layer still needs work.
In this case, you can keep the render output for the four layers that are fine, and only re-render the one layer that is in progress. This greatly reduces rendering time as compared to re-rendering all five layers.
All of your layers are fine, but you need to re-order them in the composition.
All of your layers are fine, but you need to change the blend operator for one or more layers (e.g. changed the mode of your shadow pass from Normal to Darken).
In the second and third cases, you can keep the render output for all layers. A render that only reorders layers and composites them is much faster in comparison to re-rendering every layer in your scene again.

To recycle render output for one or more layers

Render a layer. Its recycle icon changes from grey to red.
Click the layer you want to keep. Click the recycle icon to toggle it from red to green. The last rendered output image for this layer will be reused and this layer will not be re-rendered.
Repeat for all layers whose render output you want to recycle.
Note
- The recycle icon is grey until the layer has been rendered at least once. A green recycle icon saves the rendered image and allows for faster re-compositing while a red recycle icon will force re-rendering prior to compositing.
- Render output is only held in memory for your current session of Maya. Any render output is lost after you quit the current session of Maya.