Rendering passes in 3ds Max

Render passes can separate various attributes into individual frames for the likes of color, shadow, and specular shading. This allows you to perform image compositing in an image editing or compositing software, giving you control over every aspect of the final image.

1. To prepare your project for multi-pass rendering, click the Render Setup icon button (F10) in the toolbar.
   
2. In the Render Setup panel, go to AOVs > Arbitrary Output Variables (AOVs) Manager.
   
3. Open the main drop-down menu in the AOV List.
   
4. Drag and drop the type of passes you want to export into the empty space under Add New AOV Output File.
   
5. Select the location where you want to save your passes in the Output section.
   
6. In the Render Setup panel, click the Render button to start rendering all the passes.
   
7. Once the rendering is finished, load them into your preferred image editing software such as Photoshop, for further editing.