3 ms·

besides tracing fewer rays, path tracing appears to have a "chiaroscuro" aesthetic to it. in moderation, absence of light can also be a good thing.

crote 4y ago
That is primarily a result of game designers not used to lighting for path tracing. In traditional rasterized games, the only thing that matters is whether the end result looks good. This means adding things like global illumination (a magical diffuse light source which lights up stuff regardless of position), or simply making some parts of a texture brighter to make it look as if a light source is shining on it. Things like shadows are mostly pre-baked into the textures, and primitive reflections can be faked by just mirroring whatever is already on the screen. Basically, fake it until you make it. With path tracing, the renderer follows the laws of physics. If something is lit up, the light actually has to come from somewhere. And as it turns out, most light will have hit multiple objects before finally ending up at the viewer. The artist now has to make a reasonably physics model for every single object in the game - even those the player might not directly look at. It's a completely different approach - made even worse because we aren't yet at a point where every gamer has a computer which can do 100% path tracing, so you still need to support traditional rasterization for people without bleeding-edge GPUs. To get an example of the visuals possible, look at modern cinema. Disney and Pixar movies are path traced, as is probably all CGI these days. I expect games to get a more diverse look over time, as artists get more experience with it.
- kroltan 4y ago
  I am assuming you are both talking about the comparisons in the article? They are mostly terrible examples of path tracing, as they just took the original map files with the lights authored for the original renderer, erased the baked lighting, and run the new renderer with those lights. So it's not that game designers are not used to lighting for path tracing, it's just that nobody designed it. Heck, even porting maps between two versions of the same lineage of offline raytracer can result in ridiculously different outputs: https://www.youtube.com/watch?v=2JkRwPWnL_c https://www.youtube.com/watch?v=2JkRwPWnL_c Among other things, these games did not have high dynamic range lighting at all, so light data can only ever make the picture darker than the base textures. (Think of it as a layer set to "multiply" blend mode in a photo editor) So making a light brighter at some point wouldn't make things look any closer to white, just making the falloff sharper. So most lights were authored to look good in the renderer, not make any actual physical sense, as you said. That said, this approach of "just swap out the renderer" could work much better for games that work on a physically-based rasteriser workflow (mostly newer stuff, like from around 2015 and onward), because they mostly already use compliant and realistic light sources, and the baked lights and rasterisation are "merely" for performance. (a.k.a. being a game and not a 2-day-per-frame art installation) If you want to see a ray-tracing-native game, take a look at Teardown (https://www.teardowngame.com/ https://www.teardowngame.com/), it does not exhibit any of the "chiaroscuro" described, and has perfectly cromulent lighting.

crote 4y ago

That is primarily a result of game designers not used to lighting for path tracing. In traditional rasterized games, the only thing that matters is whether the end result looks good. This means adding things like global illumination (a magical diffuse light source which lights up stuff regardless of position), or simply making some parts of a texture brighter to make it look as if a light source is shining on it. Things like shadows are mostly pre-baked into the textures, and primitive reflections can be faked by just mirroring whatever is already on the screen. Basically, fake it until you make it. With path tracing, the renderer follows the laws of physics. If something is lit up, the light actually has to come from somewhere. And as it turns out, most light will have hit multiple objects before finally ending up at the viewer. The artist now has to make a reasonably physics model for every single object in the game - even those the player might not directly look at. It's a completely different approach - made even worse because we aren't yet at a point where every gamer has a computer which can do 100% path tracing, so you still need to support traditional rasterization for people without bleeding-edge GPUs. To get an example of the visuals possible, look at modern cinema. Disney and Pixar movies are path traced, as is probably all CGI these days. I expect games to get a more diverse look over time, as artists get more experience with it.

kroltan 4y ago
I am assuming you are both talking about the comparisons in the article? They are mostly terrible examples of path tracing, as they just took the original map files with the lights authored for the original renderer, erased the baked lighting, and run the new renderer with those lights. So it's not that game designers are not used to lighting for path tracing, it's just that nobody designed it. Heck, even porting maps between two versions of the same lineage of offline raytracer can result in ridiculously different outputs: https://www.youtube.com/watch?v=2JkRwPWnL_c https://www.youtube.com/watch?v=2JkRwPWnL_c Among other things, these games did not have high dynamic range lighting at all, so light data can only ever make the picture darker than the base textures. (Think of it as a layer set to "multiply" blend mode in a photo editor) So making a light brighter at some point wouldn't make things look any closer to white, just making the falloff sharper. So most lights were authored to look good in the renderer, not make any actual physical sense, as you said. That said, this approach of "just swap out the renderer" could work much better for games that work on a physically-based rasteriser workflow (mostly newer stuff, like from around 2015 and onward), because they mostly already use compliant and realistic light sources, and the baked lights and rasterisation are "merely" for performance. (a.k.a. being a game and not a 2-day-per-frame art installation) If you want to see a ray-tracing-native game, take a look at Teardown (https://www.teardowngame.com/ https://www.teardowngame.com/), it does not exhibit any of the "chiaroscuro" described, and has perfectly cromulent lighting.