I made a lamp consisting of an emissive tube and transparent glass in front of it. In cycles, it renders as fully black. Changing to the Render Engine to Eevee or the Device to CPU works fine. My materials are:

transparent material

emissive material

I also have:

  • Light Paths Max Bounces as 8 for everything but volume
  • Blend mode on the transparent object as Alpha Blend, emissive is opaque

Cycles render:



Link to blend file: https://blend-exchange.com/b/lG4YwVe3/

  • $\begingroup$ Hello, maybe share your file (only the useful objects)? blend-exchange.com $\endgroup$
    – moonboots
    Commented Nov 1, 2022 at 10:32
  • $\begingroup$ @moonboots Thanks, just added. $\endgroup$
    – Empress
    Commented Nov 1, 2022 at 14:46

2 Answers 2


Choose an IOR value of 1.3, or whatever value that is not 0, not sure why it doesn't work with GPU Compute though.

enter image description here


Make sure your max Transparency bounces is not set to 0. Also, you might try adding a Transparency node and mixing it with the textures alpha channel if you have any.


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