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Preview Scene

The Build Preview Scene button on each Scene node assembles a live Blender scene that shows you what your render setup will look like before you commit to a full render.

What the preview does

When you click Build Preview, Scene Assembler:

  1. Evaluates the node graph for that Scene node
  2. Creates (or replaces) a Blender scene named _SA_Preview
  3. Links all connected collections into the preview scene
  4. Creates one view layer per connected collection input
  5. Applies all object overrides (material, visibility, transform, RNA) to the preview scene
  6. Sets the camera, world, and render resolution from the node configuration
  7. Switches the active viewport to the preview scene

The result is a fully assembled scene you can inspect in the 3D viewport, render a test frame from, or use to check composition.

Preview ownership

The preview scene is shared — there is only one _SA_Preview scene at a time. Building a preview from a different Scene node replaces the previous one.

The Scene node button shows which node currently owns the preview:

  • ↑ Active preview is this node — the current preview was built from this node
  • Preview: [Other Node Name] — the current preview belongs to a different node

Camera Burst preview

When Camera Burst is active, the preview places one timeline marker per camera:

  • Frame 1 → Camera 1
  • Frame 2 → Camera 2
  • Frame N → Camera N

The frame range is set to 1–N and the viewport is set to Camera 1. Scrub the timeline in the 3D viewport to switch between cameras.

Clearing the preview

Click × (Clear Preview) in the N-panel or next to the button to remove the _SA_Preview scene.

Tips

  • The preview scene is a real Blender scene. You can render a single test frame from it directly using Render → Render Image while the preview scene is active.
  • Check the Scene Properties panel of the preview scene for sa_source_node and sa_source_tree custom properties that record which node and graph built it.
  • Object overrides applied in the preview match exactly what will be applied during the real render — what you see in the preview is what you get.
  • The preview scene is not saved in the .blend file. It is rebuilt fresh each time you click Build Preview.