There are two causes of light leaking under the hood of SEGI. The first is an inherent limitation of cone tracing. The premise of cone tracing is that for each traced "ray", instead of simply sampling a point of information, you get to sample an area of pre-combined information. This keeps rays that are traced in different directions more coherent and allows for tracing far fewer rays to get a smooth result. Simply put, cone tracing samples blurred data.This diagram compares naive ray tracing (left) with cone tracing (right)Now, what happens when we have a one-voxel-wide occluder in front of that light data?As you can see, with naive "brute force" sampling, each ray encounters full opaque black before it reaches the illuminated voxels, so no light gets through. With cone tracing, however, data is blurred which smears the occluder and the light information such that rays do not encounter full opaque black before reaching the illuminated voxels.The other cause of light leaking is a lack of directional light information in the voxel data. This means that, instead light bouncing forward off an illuminated surface, it bounces in all directions. This problem is helped with the Inner Occlusion Layers property and GI Blockers (see Section 4.2 of the User Guide), but is not solved completely. In the future, multiple already explored options will be considered regarding storing and reading directional voxel data to resolve this issue.