8 ms·

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 u

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 rasterisers in the last decade has exceeded even my wildly optimistic expectations. New options = good, but there's no such thing as a graphics silver bullet.

klodolph 13y ago
You might feel differently if you ever had to do shadow mapping on traditional hardware. Even in AAA games, there are tons of artifacts in the shadows. Same goes for reflections. I don't see why it's harder for artists to control the results... can you elaborate? It seems like it's going to be 90% the same. You have a point on a surface, you have a camera vector and light vectors, you supply a small piece of code and out pops a color. The major differences in the pipeline are in the scaffolding: depth tests, reflections, and shadows will be done in different ways. The differences for artists are that they'll have to learn a system with different limitations. My guess is that game graphics are going to follow the developments in movie CGI. Pixar switched to ray tracing in 2013, and games will switch when hardware powers up and expertise filters down.
- jjoonathan 13y ago
  > The differences for artists are that they'll have to learn a system with different limitations. If current-generation AAA games are any indication, either very few artists ever learned the raster workarounds or few artists ever had time to implement the workarounds. I think ray-tracing will be a game changer. Raster shadows are easy to get subtly wrong and very difficult to get right. Cube-maps are easy to get subtly wrong and very difficult to get right. Transparency is easy to get subtly wrong and very difficult to get right. The list goes on. > Even in AAA games, there are tons of artifacts in the shadows. Same goes for reflections. Exactly! I can't count the number of times I've seen shadows pointing in the wrong direction, having the wrong color, having the wrong penumbra/antumbra, casting through solid objects, etc. Cube-map reflections are even worse (yay for faucet handles reflecting forrest scenes) especially when they're moving. Expect to see a reflection slide up the body of a car as it comes to a stop? If you're not in a car-racing game, forget about it. All of those problems can be overcome with artist sweat and tears. The code has already been written and is in the big engines, but the effects still regularly fail to happen in AAA titles. Ray-tracing makes it easy to do things right. None of the raster techniques have achieved that landmark. This WILL be a game changer.
  - stcredzero 13y ago
    So, is it the case that increasing computational resources help us with getting things right? It's generally good to bet with Moore's Law.
- leoc 13y ago
  See my other comment https://news.ycombinator.com/item?id=7427486 https://news.ycombinator.com/item?id=7427486 .
tinco 13y ago
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 scene will be, up to 100% realism. Of course, we can come pretty far with the hacks as well, and it's hard to say if hardware raytracing can come close to the quality hardware shader hacks can achieve on traditional GPU's in real time.
- agumonkey 13y ago
  It's both true and false. The same reason movies still use light panes, make up etc etc. You don't want random pure reality[1]. [1] no really, you don't.
- duaneb 13y ago
  Raytracing is just one tool in a bag of necessary algorithms. For instance, there's no obvious way to extend raytracing to offer indirect lighting—all existing algorithms offer some form of tradeoff. Furthermore, many effects are flat out a pain to render with raytracing: displacement mapping, subsurface scattering, anti-aliasing, and scenes where both speed of rendering and dynamic geometry are needed. All of those require substantial thought and are non-trivial to implement. And don't forget non-realistic graphics. The problems of rendering are unlikely to become inherently easier—I don't think raytracing will ever be "end all of graphics". And while "every singly animated movie" might be raytraced to some extent, it's highly unlikely any of them use pure raytracing to achieve the effect.
  - gfodor 13y ago
    Uh, what. Sampled raytracing is the most natural approach to indirect lighting, displacement mapping, subsurface scattering, and anti-aliasing. As far as non-realistic rendering goes I am not sure how this is relevant, you can alter the properties of light and still use ray tracing, and many effects use image based techniques anyway. Raster will die in the long run, it's pretty obvious.
joesmo 13y ago
I don't think so, not with modern tools anyway. Raytracing is in my experience the technology that most closely models the real world. Most technologies used in games even today are hacks, using precomputed values oftentimes derived from ray traced models. Raytracing is quite natural to work with because it simulates real world objects and does so in a realistic manner. The only difficulty might be caused by the lack of such real-time raytracing hardware as depicted here causing slower development as one has to wait for a scene or animation to render. IMO, raytracing is indeed the pinnacle of photorealistic rendering currently.
banachtarski 13y ago
Imagine you were an artist trying to light an indoor room. Would you rather have to place hundreds of small lights everywhere and experiment for days or weeks to get the correct ambient glow? Or would you rather stick a big sun outside and call it quits? There's a reason Pixar is using physically based lighting to construct all their scenes.
jasonwatkinspdx 13y ago
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.
- james4k 13y ago
  Physically-based rendering has little to do with global illumination, and is only really about the BRDF [1] used for computing the final pixel color based on a number of inputs for that point in space. [1] https://en.wikipedia.org/wiki/Bidirectional_reflectance_distribution_function https://en.wikipedia.org/wiki/Bidirectional_reflectance_dist...
  - MrScruff 13y ago
    Well it's pretty hard to do PBR outside of a path tracer since energy conservation is a key concept.
chongli 13y ago
I've yet to see a single rasterised game come anywhere close to ray-tracing in the shadow department and that's what destroys immersion for me the most: low-resolution, aliased shadows crawling all over the place.

klodolph 13y ago

You might feel differently if you ever had to do shadow mapping on traditional hardware. Even in AAA games, there are tons of artifacts in the shadows. Same goes for reflections. I don't see why it's harder for artists to control the results... can you elaborate? It seems like it's going to be 90% the same. You have a point on a surface, you have a camera vector and light vectors, you supply a small piece of code and out pops a color. The major differences in the pipeline are in the scaffolding: depth tests, reflections, and shadows will be done in different ways. The differences for artists are that they'll have to learn a system with different limitations. My guess is that game graphics are going to follow the developments in movie CGI. Pixar switched to ray tracing in 2013, and games will switch when hardware powers up and expertise filters down.

jjoonathan 13y ago
> The differences for artists are that they'll have to learn a system with different limitations. If current-generation AAA games are any indication, either very few artists ever learned the raster workarounds or few artists ever had time to implement the workarounds. I think ray-tracing will be a game changer. Raster shadows are easy to get subtly wrong and very difficult to get right. Cube-maps are easy to get subtly wrong and very difficult to get right. Transparency is easy to get subtly wrong and very difficult to get right. The list goes on. > Even in AAA games, there are tons of artifacts in the shadows. Same goes for reflections. Exactly! I can't count the number of times I've seen shadows pointing in the wrong direction, having the wrong color, having the wrong penumbra/antumbra, casting through solid objects, etc. Cube-map reflections are even worse (yay for faucet handles reflecting forrest scenes) especially when they're moving. Expect to see a reflection slide up the body of a car as it comes to a stop? If you're not in a car-racing game, forget about it. All of those problems can be overcome with artist sweat and tears. The code has already been written and is in the big engines, but the effects still regularly fail to happen in AAA titles. Ray-tracing makes it easy to do things right. None of the raster techniques have achieved that landmark. This WILL be a game changer.
- stcredzero 13y ago
  So, is it the case that increasing computational resources help us with getting things right? It's generally good to bet with Moore's Law.
leoc 13y ago
See my other comment https://news.ycombinator.com/item?id=7427486 https://news.ycombinator.com/item?id=7427486 .

tinco 13y ago

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 scene will be, up to 100% realism. Of course, we can come pretty far with the hacks as well, and it's hard to say if hardware raytracing can come close to the quality hardware shader hacks can achieve on traditional GPU's in real time.

agumonkey 13y ago
It's both true and false. The same reason movies still use light panes, make up etc etc. You don't want random pure reality[1]. [1] no really, you don't.
duaneb 13y ago
Raytracing is just one tool in a bag of necessary algorithms. For instance, there's no obvious way to extend raytracing to offer indirect lighting—all existing algorithms offer some form of tradeoff. Furthermore, many effects are flat out a pain to render with raytracing: displacement mapping, subsurface scattering, anti-aliasing, and scenes where both speed of rendering and dynamic geometry are needed. All of those require substantial thought and are non-trivial to implement. And don't forget non-realistic graphics. The problems of rendering are unlikely to become inherently easier—I don't think raytracing will ever be "end all of graphics". And while "every singly animated movie" might be raytraced to some extent, it's highly unlikely any of them use pure raytracing to achieve the effect.
- gfodor 13y ago
  Uh, what. Sampled raytracing is the most natural approach to indirect lighting, displacement mapping, subsurface scattering, and anti-aliasing. As far as non-realistic rendering goes I am not sure how this is relevant, you can alter the properties of light and still use ray tracing, and many effects use image based techniques anyway. Raster will die in the long run, it's pretty obvious.

joesmo 13y ago

I don't think so, not with modern tools anyway. Raytracing is in my experience the technology that most closely models the real world. Most technologies used in games even today are hacks, using precomputed values oftentimes derived from ray traced models. Raytracing is quite natural to work with because it simulates real world objects and does so in a realistic manner. The only difficulty might be caused by the lack of such real-time raytracing hardware as depicted here causing slower development as one has to wait for a scene or animation to render. IMO, raytracing is indeed the pinnacle of photorealistic rendering currently.

banachtarski 13y ago

Imagine you were an artist trying to light an indoor room. Would you rather have to place hundreds of small lights everywhere and experiment for days or weeks to get the correct ambient glow? Or would you rather stick a big sun outside and call it quits? There's a reason Pixar is using physically based lighting to construct all their scenes.

jasonwatkinspdx 13y ago

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.

james4k 13y ago
Physically-based rendering has little to do with global illumination, and is only really about the BRDF [1] used for computing the final pixel color based on a number of inputs for that point in space. [1] https://en.wikipedia.org/wiki/Bidirectional_reflectance_distribution_function https://en.wikipedia.org/wiki/Bidirectional_reflectance_dist...
- MrScruff 13y ago
  Well it's pretty hard to do PBR outside of a path tracer since energy conservation is a key concept.

chongli 13y ago

I've yet to see a single rasterised game come anywhere close to ray-tracing in the shadow department and that's what destroys immersion for me the most: low-resolution, aliased shadows crawling all over the place.