Enabling GI leads to massive light leaks.

Makhecha-Reeves

Hi guys,
just started using marmoset and trying to figure out how the lighting handles. The problem i have is switching on GI leads to light leaking through floors etc. See the pictures, the first has no GI and the second has GI enabled. There are floor and ceiling polys there to block light. Its only when I enable GI the problem happens. Is it a quality setting or something?  I've been looking at this for a couple of hours but got no where.. 

Makhecha-Reeves

Changing the Voxel volume size so it just covers the building and surrounds helps. But Light from the lower floor still finds it way into the upper floor - which shouldn't really be the case... Still feels wrong to me. I've been a lighting artist for 15 years so I hopefully have a good feel for stuff like this :-)

EarthQuake

This is a technical limitation of the Voxel GI technique. Basically, VXGI works by creating a simplified, voxelized version of the scene, which it uses to calculate real-time GI. As you've noticed, when you shrink the voxel volume size, you get better detail, as you're increasing the local resolution of the voxel volume. You can increase the voxel resolution setting to high as well, though this is only recommended on high end GPUs.

If you enable the Show Voxels checkbox, you can see what is happening with the voxel volume and it should make a bit more sense. Unfortunately, for something like a larger environment or level type scene, the voxel volume will be stretched to the limits and the resulting voxel resolution and GI quality will be low.

Makhecha-Reeves

Thanks :-) you confirmed what I was thinking. I loved playing with it. Its pretty cool the amount of geo that can get covered, but i guess not too suitable for displaying a street of houses and detail.

Makhecha-Reeves

One thing was strange though, when i moved the lights in-between the floors, the geo did a much better job of blocking the light - both up and down...