Godot's CSGPolygons, when set to Subtraction operation and set as a child of another CSGPolygon, can be used to make arbitrary 3D space that would otherwise be opaque transparent. This might be extremely useful for fog of war, since you simply have these CSGPolygons follow units around.
The traditional way is to use shaders and pretty much manually update every pixel every tick, which is a bit of a headache in 3D. But it does look a lot better because you can have a naturally faded fog wall. So are CSGPolygons worth trying, or should I just stick to shaders?