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Comment by mattpharr | Hacker News Reader

Given that this is HN, I'd encourage reading and commenting on the substance of the technical paper rather than the marketing webpage.

Those ideas have indeed been around for a long time; the paper nicely cites all of the related research work. (Including among many others, a SIGGRAPH paper I wrote on the topic 18 years ago.)

I think the paper is excellent. First, there's a big gap between academic papers on a topic and the experience of actually building a real system that works for real movies. It's unusual for people in industry to take the time to write up their experiences building these systems, so I salute their making this contribution to general knowledge about rendering systems.

It's easy to carp about "all could have been done before"; that seems like an argument that could be applied to try to dismiss just about anything.

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I'll just say that I don't want to dismiss anything except for exaggerated marketing. I think it is reasonable to say that I should ignore it though.

> I think the paper is excellent. First, there's a big gap between academic papers on a topic and the experience of actually building a real system that works for real movies. It's unusual for people in industry to take the time to write up their experiences building these systems, so I salute their making this contribution to general knowledge about rendering systems.

I'm %100 with you. I love seeing the results of cache coherency used in a real scenario. I was only trying to say that the actual imagery could have been done in other renderers, albeit with more pain and I would guess more attention to level of detail.

So I'm not trying to downplay anything except for the idea that the actual movie itself couldn't have been done without cache coherent batch ray tracing, when in reality it is a big optimization that came from a bit of a leap of faith, which I think is significant enough to pay attention to.

I completely agree with you that the information in that paper is excellent and I think it's amazing that Disney is so willing to share so much information about their renderer, even though their sister company Pixar sells a renderer.

The question though is whether or not this paper should have been published at EGSR. Personally I think that an EGSR paper should either propose a novel idea or should provide a good survey of the field. I don't think this paper succeeds at either of those. Their method is 'simply' a combination of already published ideas and I don't think that they do a very good job at comparing those existing ideas.

Personally, I think this paper would have been better suited as a talk at SIGGRAPH, a publication at JCGT or a technical report (like Pixar). So: great paper, wrong venue.

I'm actually really glad they got the paper out there as a small pdf (and I'm actually glad they compared it to other commercial renderers). The reason is that it shows very real world performance results. Not only that but cache coherency optimization results are shocking and illuminating to many people because it seems so counter intuitive when there technically aren't more instructions being ran.

Every paper I read now I am looking for all the things that were left out, how the comparisons have been changed for each scene to make that particular algorithm look good etc.

It answered a big question lingering in my mind that I haven't been able to actually try out.

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