Entry 8 : Back to Nuke with all those AOVs

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 Now we'll see what the final steps are once the renders are complete. So, now we have multiple folders each for one of our render layers and each frame is rendered out as an EXR file and each of them has every AOV merged within it. 

The Layer Contact sheet node shows all of the nested AOVs in the EXR file

1. Import all the rendered sequences into Nuke.

2. Attach a shuffle node to the the sequence and change the input layer to one of the AOVs from the list. Add as many shuffle nodes as needed )Motion blur and z depth doesn't need a shuffle node).

3. Add an Unpremult right after the render sequence, before the shuffle nodes and a premult node after merging all of them.

4. Add a Merge nodes and connect all of the shuffle nodes consecutively. In the end after all the merges the output should match the Beauty pass render. Set merge mode to plus.

5. Use a Copy node to copy the alpha from the render sequence to use for the Premult node.

6. We can attach grade, color correct and any other nodes we want under the respective AOVs shuffle node to tweak them accordingly.

7. Add the shadow layer under the geo layer, add the backplate under everything else.



VectorBlur node- used to extract and manipulate aiMotionVector AOV from the renders. Adjust amount of motion blur, higher value results in longer blur tails.

Low Motion Blur

High Motion Blur


Defocus Node - the CG assets maybe too sharp and high rez compared to the elements in the actual footage, so we use this node to add some blur throughout the CG element not just the edges.

ZDefocus node- used to extract and apply depth of field data from the Z AOV in the renders. Set the depth channel to Z.depth and math to depth. Set focal plane under the output>focal plane setup, anything in this area will be in focus and rest will be blurred. Regions colored red are infront of the focal plane and bule are behind it both of them are out of focus. Increase depth of field value, size and maximum to get desired amount of blur.


(from left) Focal point set on the sphere up front, focal point in the middle, focal point at the farthest from the camera


Tips:

1. Add Multiply as the merge mode for Ambient occlusion.

WHY? AO adds darkness to occluded areas to produce a fake shadow effect. The AO map only has greyscale values, so it is multiplied with the base color value which darkens the base color producing the pseudo shadow effect.  

2. Use [value in1] in the node settings for Shuffle nodes to automatically rename them based of the input layer.



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