How is sun modeled when doing ray-traced rendering? Is it part of the scene, like a sphere with a centre in some far location or it is just considered as a point?
Also regarding sending shadow rays to the sun, is it, again, sampling a sphere or just sending shadow rays to one point?
If you take sun as a point, you can not have shadows smoothing/blurring for tall objects. Notice how due to measurable sun angular size, the sahdow gets smoother/blurry the farther it lies from the runner:
For simplicity you can assume sun is a luminous disc facing your scene, placed far far away.
