How to enable Intel denoiser using python?

Question

I'm creating a scene from scratch in blender (2.83+) using python, and I'd like to turn on Intel denoiser for the Cycles render output.

I've got some code but it's not working yet:

  bpy.context.view_layer.cycles.denoising_store_passes = True
  bpy.context.scene.use_nodes = True

  tree = bpy.context.scene.node_tree # inputs, outputs, nodes, links
  comp = tree.nodes[0]               # result goes into here
  render = tree.nodes[1]             # render layers: images come from here
  denoise_node = tree.nodes.new(type='CompositorNodeDenoise')
  # Link it in:
  links = tree.links
  # links.new(output ---> input)
  link = links.new(denoise_node.outputs[0], comp.inputs[0])
  # XXX: find outputs by name
  # XXX: use "Noisy Image" output (31) rather than "Image" (0)?
  link = links.new(render.outputs[0], denoise_node.inputs[0]) # Image
  link = links.new(render.outputs[32], denoise_node.inputs[1]) # Denoising Normal
  link = links.new(render.outputs[33], denoise_node.inputs[2]) # Denoising Albedo

The problem is that even though I've enabled bpy.context.view_layer.cycles.denoising_store_passes = True it doesn't seem to have taken effect by the time the rest of my code runs; the render node still only has 31 outputs. It should have 39.

Anyone know how I can wait for that setting to take effect before continuing?

Answer 1

I don't think the problem is with the setting not taking effect. I think the node is there, you just need to reference it by name instead of index since the numbers you are using aren't working.

This should fix it:

link = links.new(render.outputs['Denoising Normal'], denoise_node.inputs[1]) # Denoising Normal
link = links.new(render.outputs['Denoising Albedo'], denoise_node.inputs[2]) # Denoising Albedo

There is a plugin on GitHub that does this: blender_instant_denoise. That's where I found the answer.