Rendering Correct Alpha Channel for Refractive Materials in Redshift

A few years into my Redshift journey, I realized something simple yet profoundly irritating: you can have a beautiful CG-glass object—perfectly lit, physically accurate refractions, caustics dancing just right—but when it hits the composite, the alpha channel is all wrong. A flat white blob. An opaque mask where transparency should live. The glass behaves like plastic, and suddenly 90% of your compositing magic goes into fix-up rather than artistry.

Check out this video to see a step-by-step breakdown on how to fix this issue when using Redshift as your render engine inside of Cinema 4D:

https://www.youtube.com/watch?v=66d3j0Z4GHg

So...next time you’re working with glass...lens elements...acrylic...transparent plastics—or any material where you want to see the world through it rather than behind a white mask—take the extra two minutes before you hit render to check that you have the correct alpha channel compositing workflow enabled.

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