I grabbed a Sketchfab asset and downloaded as GLB (left) and USDZ (right) and imported them into Omniverse and put them side by side. The GLB importer sets the emission strength really high and the walls look darker than the USDZ file (both are in the same scene with same lighting etc.) I know there are efforts to standardize the import of GLB into USD, but the current GLB import in this case is clearly not ideal. The USDZ generated by Sketchfab for the same model looks much better. Winding down the emission alone made a big difference.
Update: Hmmm, the image on the right might look better, but if you turn all scene lights off, the room still visible as normal. Put a character in the room, and that character is dark in ray trace mode.
Summary: Mixing assets from different sources is hard! Not only does lighting matter, but the materials matter in how they react to light. And things can vary a lot between ray trace and path trace.
Are there any good references for “good” USD material definitions?
This is pretty normal workflow.
1 Use the USD convert not the GLB
2 Delete all the lights and cameras. You can recreate them much more accurately.
3 Next turn on path tracing in LIGHTS OFF mode and look for self-glowing materials. That will mess you up. Find them and turn off their self-emissions.
4 Hide all of the glass windows unless you really need them, and it will make the lighting more efficient, faster and cleaner.
5 Use a fresh new environment from our library. I think the 3rd dynamic sky. Set the time of day to your liking.
6 Set the exposure you want
7 Add a little FFT and Vignette
This one started as “Omniverse converts GLB files to USD very differently to how other people do it and it does not look good” to “Sketchfab does weird things to get scenes to look good without lights and I don’t care that OV does not make it look the same - it has to be fixed anyway”. (I have not seen any lights - it’s all emissions.)
Almost want a little extension to go through and do that stripping. (Importing with UsdPreviewSurface option set had the same problem.)
Then need to fiddle the lighting if care about how nice it looks, to get the most out of it all.
Well SketchFab is not the best. Try TurboSquid or Kit Bash. Much much higher quality scenes. Sometimes it makes sense to just grab the geometry and scrap everything else and rebuilt in OV correctly. Correct materials, lights, cameras etc.
