I´m currrently in depth trying to get used to all the options I have when building light with the goal to get the best possible result with a sharp GI without artefacts.
The most annoying thing I constantly run into is the fact that lightmaps are not accessible through the object they are assigned to. We only can access lightmaps through the world settings tab, where it´s nearly impossible to find a lightmap to a corresponding object (Once a project reaches a certain size). Basically there are two main reasons why I would would need this. MipMaps and compression. On most objects compressed lightmaps are ok. But when you have a blank white wall in an architectural project for example it makes sense not to use compression on just this object. Also there are often cases where I want certain objects not to use Mip Maps for lightmaps. For example furnature with small joints. Lightmaps with Mip Maps produce dirty artefacts when moving away from the object.
While in theory all these settings should be possible with the Engine as it is, it´s impossible as you cannot really access these settings from an object. It would be great if the Lighting tab within a Mesh is extended to have options for compression and mip maps so you can make per object settings before lighting is calculated or easily access a specific lightmap to make changes afterwards.
I ran into a problem when turning compression off. Once the lighting is calculated the lightmaps on some objects appear very blurry. See attached screenshot. the problem seems to be the LOD Bias in the lightmap. The default LOD Bias 0 is very blurry. I need to set it to 1 or turn of Mip Maps to get sharp lightmaps as I would expect it. This of course only works in my test scene with a handfull of objects where I´m able to find lightmaps.
I have another question about Volume Light samples. They seem to get only calculated for a certain distance above a static object. See attached screenshot. So dynamic objects that leave this distance are rendered dark. How can I change this so that volume light samples fill for example an entire Lightmass Importance Volume ?