I'm trying to have my stained glass window cast a colorful reflection onto the ground of my scene. I want a distinct reflection, and the only lights in my scenes are an HDRI image for the World, and a Sun lamp to get the window reflection you see here: enter image description here

I'm not sure what to do. Textures: https://workupload.com/archive/8uQ3ArXuG2

  • $\begingroup$ Hello could you please pack your images before sharing? File >External Data >Pack Resources $\endgroup$
    – moonboots
    Nov 7, 2023 at 7:46
  • $\begingroup$ When I pack them unfortunately its way too big to upload then $\endgroup$ Nov 7, 2023 at 8:02
  • $\begingroup$ It's not reflections you are talking about if the light goes through the glass. It's called caustics. There can be reflective caustics as well, but you are probably after refractive caustics here. You can look it it up. They are very computationally expensive - be prepared for the render times to increase dramatically. $\endgroup$ Nov 7, 2023 at 8:02
  • $\begingroup$ So use another platform like workupload for example, only keep the useful objects $\endgroup$
    – moonboots
    Nov 7, 2023 at 8:02
  • $\begingroup$ I was about to say what @MartynasŽiemys has just said.. I guess you could save the expense with a reasonable fake, (purpose-built projector) if acceptable. $\endgroup$
    – Robin Betts
    Nov 7, 2023 at 8:05

1 Answer 1


In your current setup the image gets lost, maybe make it simpler, like plug the image into the Transparent shader and plug the Transparent into the Output:

enter image description here


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