Hyperion Systems Activated

August 2, 2015 12:36 AM

Disney's Practical Guide to Path Tracing (YouTube) Hyperion handles several million light rays at a time by sorting and bundling them together according to their directions. When the rays are grouped in this way, many of the rays in a bundle hit the same object in the same region of space. This similarity of ray hits allows us – and the computer – to optimize the calculations for the objects hit.

Surrounding article
Publication: Sorted Deferred Shading for Production Path Tracing (PDF)

posted by CrystalDave (8 comments total)

We sort large, potentially out-of-core ray batches to ensure coherence of ray traversal. We then defer shading of ray hits until we have sorted them, achieving perfectly coherent shading and avoiding the need for shading caches.

I'm pretty sure I patented this back in 2006-2010. Back then, most ray tracing systems were doing depth-first traversal. We did breadth-first traversal with sorting and scheduling to create parallelism for intersection testing and shading.

Ha ha, I better sic my lawyers on Disney to see if they're infringing.
posted by ryanrs at 1:34 AM on August 2, 2015 [20 favorites]

At the time, we were focusing on real-time ray tracing with dedicated hardware (basically a ray tracing GPU). Our prototype did decent looking, VGA res global illumination on large scenes (millions of triangles) with something like 20 rays/pixel at 20-ish fps*. And that was with a 90 MHz fpga connected to a stick of ddr2 laptop ram. We figured that with a custom chip on a commodity 90nm process (the not-bleeding-edge tech at the time), we could do pretty good, fullscreen, realtime raytracing.

Alas, various financial setbacks occurred, including Bernie Madoff personally ripping off some of our angel investors and a recession in 2008. This really fucked up our plans to raise enough money to tape out our asic. It was a pretty cool chip though! We even rendered scenes with the gate level simulation, which took weeks to run, ha ha.

Anyway, that tech is now owned by Imagination Technologies, so maybe you'll see it in a future cell phone or something. There is silicon to do it in the latest PowerVR gpus, but I don't know if any OEMs are actually using it in their devices. Maybe it will pop up in the iPhone 7.

*all specs vaguely remembered from 5+ years ago and possibly wrong
posted by ryanrs at 1:56 AM on August 2, 2015 [17 favorites]

It's amazing how much hard computer work it takes to be inferior to what was formerly the best traditional animation studio in the world...!
posted by markkraft at 3:25 AM on August 2, 2015 [4 favorites]

I'm a believer, no doubt in my mind.
posted by Samuel Farrow at 7:52 AM on August 2, 2015

Anyway, that tech is now owned by Imagination Technologies, so maybe you'll see it in a future cell phone or something. There is silicon to do it in the latest PowerVR gpus, but I don't know if any OEMs are actually using it in their devices. Maybe it will pop up in the iPhone 7.

The GR6500 which includes the realtime raytracing hardware (their budget is 300 million rays a second) has just been taped out last month.
posted by Talez at 8:01 AM on August 2, 2015 [3 favorites]

like a billiard ball on a pool table

I see what you did there.
posted by Wemmick at 12:47 PM on August 2, 2015

This is where PowerVR GR6500 steps in to save the day: the PowerVR Wizard ray tracing GPU provides a budget of 300 million of rays per second in a mobile power envelope and is designed to comfortably sustain real-world applications with highly incoherent rays, enormous scenes, and shaders that execute hundreds of instructions to resolve each ray (not just technical demos.) -GR6500 press release, emphasis mine.

Oh man, that bit about tech demos brings back so many memories of the early days. When we showed off our simulations, it always felt like we spent half our presentation time explaining why performance results from this paper or that tech demo were actually bullshit based on contrived geometry, or really particular scene geometry or shading, or something that wasn't quite entirely honest.

Our scenes, on the other hand, were just based on models we downloaded from turbosquid. In the early days, we used a Nissan 300ZX model a lot, because both James and I drove one in real life. Later on James bought an Audi R8, so our renderings began to show off that car a lot.


It's so weird that this tech ended up in a mobile GPU first. But ray tracing on the desktop and console markets was a really hard sell. Games are really the only thing that sell those GPUs, and game makers generally want their game to run on a broad range of hardware. So if Sony, say, built a console that did raytracing, most games probably wouldn't use it, since using the dedicated hardware would lock them out of PCs.

It's a shame really, since with current GPU transistor budgets, you could make a really nice desktop ray tracing GPU. On the other hand, maybe the mobile market is in a better position to show off new ray tracing tech. If the iPhone 7 did raytracing, there are thousands of app developers that would immediately start cranking out little games and things to show off what the hardware could do. The Apple app ecosystem/culture is much better at showing off new, device-specific tech, I think.

Anyway, that's my prediction. Ray tracing in the iPhone 7/iPad, and a flurry of cute games and crap to take show it off. It's going to happen on Apple first, not Android, because Apple evangelizes new tech, and Android designs for the common denominator. The mobile carriers have too much control over Android hardware, and as everyone knows, mobile carriers are really dumb about nifty new hardware/software.

(I should mention that I haven't been privy to insider info at Caustic or Imagination since about 2009. The above commentary is not the voice of an informed stakeholder, but merely the wishes of a long departed founder who really hopes that his tech finally makes it into a real product, damn it!)
posted by ryanrs at 5:12 AM on August 3, 2015 [1 favorite]

BTW, I realize I'm kind of derailing a thread that was supposed to be about some Disney thing. But there have been so few comments, that if anyone wants to just chat about general ray tracing stuff, that would be fun.
posted by ryanrs at 5:13 AM on August 3, 2015