Lumen translucency in "lumen scene" mode

Hey guys, any idea why an object using translucency e.g, a vase, disappears when i check the scene In 'view lumen scene" I thought 5.1 supported ray traced translucency?

Obviously perfectly fine in lit mode. Was just curious

This topic has been moved from Community to Rendering.

When posting, please review the categories to ensure your topic is posted in the most relevant space. Hopefully, this new category will help you to get an answer.

In the meantime, good luck and happy developing! :slight_smile:

Where did you read this? 5.1 supports higher quality reflections (including hardware raytraced hit lighting) on translucent materials, but that doesn’t really mean having translucent surfaces represented in the Lumen scene.

I’ll give a bit of a technical explanation if I may:

  • To my knowledge, translucent objects aren’t actually added to the lumen scene, I could be wrong however. Volumetric/masked objects (EG foliage) are supported in SWRT via stochastic distance fields, and I’m unsure of HWRT’s method. That’s not the same as transluent, and it’s more intended for foliage and the like than hard surfaces.
  • I believe translucent surfaces in lumen work by drawing the game scene with just the visible translucent objects (depth peeling), tracing reflections to the lumen scene from those objects, then drawing the game scene again. As this operation is only done for the first layer of translucency, translucent objects seen in translucent reflections are instead lit via lumen’s radiance cache. For it to be done recursively, you’d need translucency able to reflect other translucency, which would to your point require transluent objects in the lumen scene.

So essentially, any surface (even Niagara fluids, I’ve tested it) can receive lumen reflections, but only surfaces either covered by the surface cache or hit lighting can cast reflections.