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PowerVR GR6500: Ray tracing is the future and the future is now

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Re: PowerVR GR6500: Ray tracing is the future and the future is now

#42
post #34

Earlier quoted context omitted.

Ray tracing works backwards from the way actual optics works. It sends out a ray for each pixel and then finds out what it falls on then does math to figure out what it should look like. In a simple example, you have a few light sources and you trace a ray back to an object (polygonal surface), then you shoot off other rays from there toward the light sources (or you shoot off potential reverse reflection rays). If s…

This sounds somewhat wrong. Ray tracing is just another term for path tracing, as paths are made up of traced rays. A naive camera-to-light witting ray tracer is still a sampling path tracer but has bias towards a specific subset of paths, namely those which follow specular bounces from the eye to the light or those which have one diffuse bounce. Much of the progress in photorealistic rendering has come from improvin…

I thought I was clear that path tracing and ray tracing shared similarities. But ultimately they differ in several key ways.

For example, ray tracing tends to be deterministic, and it starts at the view frame and moves toward the scene and then light sources. Path tracing has no such constraint. Modern path tracing techniques use a combination of ray-tracing-like paths as well as paths beginning from light sources (gathering rays and shooting rays, in the parlance of the field).

In principle you could consider path tracing to be some sort of specialized subset of ray tracing (or vice versa for that matter) but in practice it is different enough in its specifics and implications that it makes more sense to treat it as merely related.

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#43
post #40
post #16

Earlier quoted context omitted.

I'm sorry man, but that sounds crazy. Raytraced scenes are much easier for artists to control the results because things actually behave like you would intuitively expect (if the amount of rays is high enough). If raytraced scenes were hard to control, why would every single animated movie be raytraced? Raytracing really is the be all and end all of graphics. The more rays you can render, the more realistic your scen…

> If raytraced scenes were hard to control, why would every single animated movie be raytraced? That's a bit of a stretch. Pixar didn't use ray-tracing until Cars [2006]. Even then, it was only applied for secondary effects. It wasn't until Monsters University [2013] that they produced the majority of a movie using ray-tracing [1]. That's a recent development, IMHO. [1] http://thisanimatedlife.blogspot.com/2013/05/pi…

But that is because of hardware capability... i.e. computers weren't good enough for artists to work with... wasn't it?

I've been out of the 3D world for a while, but Ray tracing was the be-all-end-all/holy grail of 3d. It is simulating light... you can't do better than physics.

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#44
"... the potential that these technologies have to revolutionize the user experience from mobile and console gaming to virtual and augmented reality."

I've been interested in ray-tracing since the early '90s, and I'm glad it's finally coming to real-time, but this isn't going to "revolutionize" shit. It's going to make 3D games and VR slightly prettier than they were. It's not going to enable new styles of gameplay or new modes of interaction. We will never again see anything like the enormous forward leaps in realtime graphics that happened during the '90s.

I'm also a bit put off by their comparison showing that PowerVR has better reflections, shadows, and transparency than a raster engine with reflections and some shadows turned off and a very poor choice of glass-transparency filter.

On another look, I don't even know what they're going for with the shadows. The rasterized image has "NO SHADOWS" printed right between the shadows of a building and a telephone wire, and their hybrid render has the light from the diner windows casting shadows across outside pavement in broad daylight. Bwuh?

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#46
post #9
post #7

I dont know much about the differences but the samples images (like the yacht) don't look particularly impressive or real to me.

Mobile. They can do that on mobile. :)

Today's mobile devices, especially the higher-end ones, are quite powerful. They offer more processing power, memory and storage than laptops did just a few years ago, and desktops just a few years before that. So I don't think that "doing it on mobile" is really that powerful of an argument any longer.

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#47
post #46
post #9

Earlier quoted context omitted.

Mobile. They can do that on mobile. :)

Today's mobile devices, especially the higher-end ones, are quite powerful. They offer more processing power, memory and storage than laptops did just a few years ago, and desktops just a few years before that. So I don't think that "doing it on mobile" is really that powerful of an argument any longer.

Real-time raytracing isn't something we've had on mobile. Which is kind of the point of this article...

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#48

What's the difference between ray tracing and path tracing? And could we have a path tracing chip? This demo was pretty impressive. I think they said they used 4 Titans at 720p. https://www.youtube.com/watch?v=aKqxonOrl4Q

Ray tracing works backwards from the way actual optics works. It sends out a ray for each pixel and then finds out what it falls on then does math to figure out what it should look like. In a simple example, you have a few light sources and you trace a ray back to an object (polygonal surface), then you shoot off other rays from there toward the light sources (or you shoot off potential reverse reflection rays). If s…

I looked into this because I design optics. Too bad I can't use graphics oriented ray tracing to analyze designs!

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#49

Interactive raytracing is the future both in mobile and desktop. My project http://clara.io , an online 3D modeler + renderer, recently gained the ability to do embeded interactive ray traced 3D embeds using V-Ray (one of the best and most accurate renderers in the world). It works best on Chrome, Firefox and Safari: https://plus.google.com/u/0/+BenHouston3D/posts/DYq2RKJENC5 Here is another example: https://twitter.…

That's really great. Did you use emscripten or is the renderer programmed in Javascript?

Re: PowerVR GR6500: Ray tracing is the future and the future is now

#50
post #3

It's best to remember that ray tracing isn't the be all and end all of graphics since it's far harder for artists to control the results than the other hacked up ways. One consequence of this is their example comparison, where I think it's entirely subjective to say the ray traced output is better. Neither is particularly great. The big win is around indirect lighting, but the development of that in standard rasteris…

I'm sorry but there is a pronounced industry trend exactly against what you argue. Physically based rendering is winning out almost everywhere. A straightforward path tracer is capable of simulating nearly all the physics of light to any desired degree of fidelity. Part of why it's won out is that it's actually far simpler for artists to work in terms of real world material concepts vs tuning abstract parameters in fake models that can be coerced into to looking real. Eg "dusty metal with this albedo map" vs maps for parameters in some mutilated and extended phong shader.
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