I can’t open my projects in preview 7 without crashing so I will answer based on preview 6:
- Denoiser creates seams between meshes
- Denoiser creates colored artifacts when lightmap compression is enabled (I think this is due to denoising happening after compression, but that’s just a guess)
- Volumetric lightmap doesn’t build properly and is very noisy
- First bounce ray guiding sometimes creates blocky artifacts
- Stationary Skylights are unsupported
- Area shadows for stationary directional light produces different results than CPU lightmass
- Doesn’t seem to sample light color properly from the skyatmosphere system resulting in much whiter color temperature from CPU lightmass
- Intensity of static lights behaves strangely depending on the light settings, not consistent at all with stationary lights
- Most lightmass features are unsupported (Indirect lighting intensity, diffuse boost, AO, ao material mask, etc.)
Probably lots more I am forgetting.
If you’re fine with a bit of noise and you have a very static scene then it’s probably usable. For what does work, the results are excellent and if you’re making an archviz scene with lightmap compression off you can get really gorgeous results. Unfortunately because of the issues with the denoiser I find I have to turn it off and max out the sample count.
For dynamic scenes, I would say it is not usable at all. Mainly this is because you can’t generate a proper volumetric lightmap, but also because of the generally sparse support for stationary light features. For example, the inability to adjust the indirect lighting intensity means you can’t use a stationary light in a room where you can turn a light on and off.