Lecture 13: Global Illumination & Path Tracing (43)

christineelu

How would the emission of light/surface light field be calculated for moving scenes and how would time be factored into this?

mhallac

What's nice here and kind of helps with the intuition is that, as seen in the previous slide, since ||K|| < 1, each successive power of K will get closer to zero, and after each bounce the proportion of the emitted light that is added decreases as K^n converges to zero

aravind00r

@christineelu's question, I believe it is calculated frame by frame, taking advantage of caching and static area's as best as the rendering engine can. There are also baked in lightmaps, which are sorta like pre-calculated lighting values for many static or even some dynamic parts of scenes in pre-processing. I remember having to rebake the lightmap many times as I adjusted scene objects in Unity. Cool video of its use in games. https://www.youtube.com/watch?v=eGmXDOGjKPA.

How would the emission of light/surface light field be calculated for moving scenes and how would time be factored into this?

What's nice here and kind of helps with the intuition is that, as seen in the previous slide, since ||K|| < 1, each successive power of K will get closer to zero, and after each bounce the proportion of the emitted light that is added decreases as K^n converges to zero

@christineelu's question, I believe it is calculated frame by frame, taking advantage of caching and static area's as best as the rendering engine can. There are also baked in lightmaps, which are sorta like pre-calculated lighting values for many static or even some dynamic parts of scenes in pre-processing. I remember having to rebake the lightmap many times as I adjusted scene objects in Unity. Cool video of its use in games. https://www.youtube.com/watch?v=eGmXDOGjKPA.