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I'm trying to render an RGB image and corresponding depth image for a simple scene consisting of a single object. I've been able to render the RGB image without any problem but I'm unable to generate the depth image. I've tried it a couple of ways with no success. Any help will be hugely appreciated. First method: Reading the Z-buffer:

bpy.context.scene.use_nodes = True
tree = bpy.context.scene.node_tree
links = tree.links
for n in tree.nodes:
    tree.nodes.remove(n)
rl = tree.nodes.new(type="CompositorNodeRLayers")
composite = tree.nodes.new(type="CompositorNodeComposite")
composite.location = 200,0
links.new(rl.outputs['Z'], composite.inputs['Image'])
scene = bpy.context.scene
scene.render.filepath='depth.png'
bpy.ops.render.render(write_still=True)

This gives an all white output image. I tried some variations based on comments online, like linking to composite.inputs['Z'], saving into a .exr file instead of .png. But in all cases, it saves a .png file which is either all black or all white. I have seen examples where I can link to a CompositeNodeViewer and then read bpy.data.images['Viewer Node'].pixels, but it is too slow/clunky for my use. Second method: Using a mist pass:

scene.render.layers['RenderLayer'].use_pass_mist = True
scene.world.mist_settings.start = 0
scene.world.mist_settings.depth = 10
links.new(rl.outputs['Mist'], composite.inputs['Image'])
scene.render.filepath = 'depth.png'
bpy.ops.render.render(write_still=True)

This creates a segmentation mask of the image, 0 in background and 1 in object pixels. I want a depth image, with gradation between [0, 255] for the foreground pixels also. What am I doing wrong ? Thanks for any help in advance !

Siddharth Mahendran
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  • Do the answers on this question help? https://blender.stackexchange.com/questions/1555/how-can-i-get-a-depth-of-field-render-pass/1563 – Ray Mairlot Oct 16 '17 at 16:51
  • Thank you for the response. I'll have a look at the Normalize and Map Range nodes. I don't want to defocus the image (scale the RGB with depth). I just want the depth itself as a separate image, something along the lines of a Kinect output say (rgbd image). I'm not too confident about trying the "Creating a Black and White depth image" answer. The issue is that I'm coming to blender from python instead of the other way around. I have zero experience with the Blender GUI, but I understand what the python code is doing. – Siddharth Mahendran Oct 16 '17 at 17:33
  • Have a look at these instructions. This is not python, but I am confident that it is possible to express semantic with python. – DiCaprio Oct 27 '17 at 09:29

0 Answers0