[altrego99]

I actually found it disappointing, compared to some other similar Disney material I've seen earlier. It is perhaps too simple.

Certain things are so grossly oversimplified, they are misleading.

For example, how does sorting rays following similar direction help? The history book analogy is appalling. It might give the misguided interpretation to a kid that it is always better to sort items - e.g. before summing a few numbers, may be sorting them is a good idea, or before map operations may be sorting them will ease the task for a computer, etc.

[davvid]

how does sorting rays following similar direction help?

They're probably alluding to Disney's Hyperion renderer[1]. Sorting rays helps with cache coherency.

[1] https://disney-animation.s3.amazonaws.com/uploads/production...

[solidangle]

Yeah, I was a bit disappointed that they started focusing on their own renderer instead of just explaining more of the basics of path tracing. Note that it isn't necessary at all to sort rays, although it can make things faster if done correctly. Also note that Disney isn't the first to consider sorting rays and tracing them at the same time, similar research was done in the 90s.

[shogun21]

I thought the homework example was a good analogy for context-switching.

The big thing they were trying to get at is there are some clever tricks we can do to make these massive calculations more efficient.