Get anti-aliased depth map in cycles render

Question

I know that in Cycles Z pass is not anti-alisased while Mist pass is normalized anti-aliased. I need the real depth of each pixel (like the Z pass) but with anti-aliased. I don't know if getting that from the Z-pass (by making it anti-aliased) or from the Mist pass (making it not normalized) would be feasible and easier?

The real problem is when looking at the output Z pass, the pixels around thin objects like branches, grass stocks, are kinda sparse and missing. I doubt that could be because anti-aliasing is not on. I wouldn't want to post-process that with filtering, since they may create artifacts. So I am trying to get better anti-aliased depth image.

Answer 1

You can easily extend the mist pass again.

When measuring pixel values with ⎈ Ctrl LMB, be sure to set the display color color management to None otherwise your values will not be read linear.

• Define an infinity limit, a value which is the maximum distance from the camera. Infinity will assume this value as well, objects beyond will clamp to this value. I used 1000. Set the mist depth to this value.
• Set the mist start to 0.

Render a separate mist pass.

In Compositing:

• Invert the Mist pass (1 - Mist).
• Multiply it with the depth limit.

Remember to save as an .exr to retain values > 1.