The lighting is calculated completely on the fly via a naive trace to each light. While this hurts performance it does allow us to offer very pretty lighting compared to the other render modes.
There is. The criteria is based on the accumulated alpha value and it isn’t tuned for any particular quality/performance so YMMV.
No.
The renderer more or less works by converting the particle data to a sparse 3D voxel structure, then taking steps with an upper bound of “Max Step” and adaptively refined util the result converges or the step goes below “Min Step”. Rays traced for shadowing information are not adaptive and always move by “Max Step” (at least in the current implementation).