How to Combine Multiple Render Layers in Blender

Combining multiple View Layers in Blender allows you to render separate scene elements—such as foreground characters, complex backgrounds, and specialized visual effects passes—and assemble them into a cohesive final image or animation. This guide explains how to configure distinct View Layers, import them into the Compositor, merge them using blending nodes, and output a single unified composite.

1. Set Up Your View Layers

Before compositing, ensure your scene collections are separated across different View Layers.

  1. Navigate to the top-right corner of the interface in the Outliner window.
  2. Click the View Layer dropdown and click the Add View Layer icon (or copy the current one).
  3. Name your layers logically (for example, Foreground and Background).
  4. Select a layer and use the Outliner visibility toggles to enable or disable collections. You can use the Holdout (creates an alpha cutout of the collection) or Indirect Only options on specific collections depending on your layer needs.
  5. In the Render Properties panel under Film, enable Transparent so that empty areas render with an alpha channel instead of the world background.

2. Open and Enable the Compositor

  1. Switch to the Compositing workspace from the top workspace bar (or open a Compositor editor window).
  2. Check the Use Nodes box at the top of the Compositor editor.
  3. You will see a default Render Layers node connected to a Composite node.

3. Add and Configure Render Layer Nodes

  1. Select the existing Render Layers node and set its layer dropdown (at the bottom of the node) to your primary layer (e.g., Background).
  2. Press Shift + A, navigate to Input > Render Layers, and place a new node.
  3. On the new node, select your second layer from the dropdown (e.g., Foreground).
  4. Repeat this step for any additional View Layers in your project.

4. Merge Layers with the Alpha Over Node

To stack layers that contain transparency, use the Alpha Over node.

  1. Press Shift + A and go to Color > Alpha Over.
  2. Connect the Image output of your background layer into the top Image input (Image 1) of the Alpha Over node.
  3. Connect the Image output of your foreground layer into the bottom Image input (Image 2) of the Alpha Over node.
  4. If working with three or more layers, add additional Alpha Over nodes in a chain: connect the output of the first Alpha Over node into the top input of the next one, and feed the subsequent layer into the bottom input.

5. Route to the Composite Output and Render

  1. Connect the final Image output of your last Alpha Over node to the Image input of the Composite node.
  2. (Optional) Add a Viewer node (Shift + A > Output > Viewer) and connect the final image to preview the composite in the backdrop (enable Backdrop in the header).
  3. Press F12 to render the scene. Blender will render each View Layer sequentially and process them through the node tree to produce a single composite output.