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SIGGRAPH 2013 Master Thread

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mhagain    13430

One of the papers that caught my eye this year in a bad way was the pre-computed cloth simulation. Essentially they took a (small) set of known character animations, put a cloak on the character, and precomputed every potential pose for the cloth and saved it in some kind of compressed 70 MB graph structure. Their proposal is that instead of trying to run cloth at runtime, you do it offline (4500 hours for this, if memory serves) and look up the results in the structure.

 

The paper tries to pitch this for upcoming gen real-time, which I find comical. The set of animations is small, the data is enormous to be traversing at runtime, and betting memory against compute power when GPU compute is coming fully into its own is tone-deaf at best -- if not completely insane. (Nevermind the implications to a production pipeline when the animation requires several thousand hours to regenerate.) While the technical aspects of the work may be well done, I really hate the core idea of this work and IMO it's a good example of bad academic work being pitched to industry.

 

So it's keyframe animation given a fancy name?  Yuck.

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Kaptein    2224

Lovely stuff smile.png

Wish I was there, although I'm not quite qualified to be there tongue.png

 

My favorite so far:

Highly Adaptive Liquid Simulations on Tetrahedral Meshes

Edited by Kaptein

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Promit    13246

Highly Adaptive Liquid Simulations on Tetrahedral Meshes

Looks like a way of integrating SPH into arbitrary spaces, I guess? I'm not very familiar with fluid simulation work, but the simulation time for their demos is on the order of five hours. That's a bit out of reach sad.png Maybe if they'd precomputed it all and stored it in a giant compressed graph... :D :D

Edited by Promit

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FreneticPonE    3293

One of the papers that caught my eye this year in a bad way was the pre-computed cloth simulation. Essentially they took a (small) set of known character animations, put a cloak on the character, and precomputed every potential pose for the cloth and saved it in some kind of compressed 70 MB graph structure. Their proposal is that instead of trying to run cloth at runtime, you do it offline (4500 hours for this, if memory serves) and look up the results in the structure.

 

The paper tries to pitch this for upcoming gen real-time, which I find comical. The set of animations is small, the data is enormous to be traversing at runtime, and betting memory against compute power when GPU compute is coming fully into its own is tone-deaf at best -- if not completely insane. (Nevermind the implications to a production pipeline when the animation requires several thousand hours to regenerate.) While the technical aspects of the work may be well done, I really hate the core idea of this work and IMO it's a good example of bad academic work being pitched to industry.

 

Completely agree, and having watched the video (correct me if I'm wrong) it only seems to run through it's precomputed tree, rather than offer any interaction with other obejcts, which would require a much larger data set and even more precomputation time at least.

 

Regardless, here's where the presentations for the Advances in Realtime Rendering course will be posted: http://advances.realtimerendering.com/s2013/index.html

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Promit    13246

MeshGit: Diffing and merging meshes for polygonal modeling sounds pretty cool. Version control for asset creation tools has been on my mind for a while now.

Cool idea and work, though as usual for the university crowd they only look at the geometry and ignore all other vertex attributes. The paper includes a throwaway line claiming that including other attributes would be trivial, but I'll believe it when I see it.

 

Jeez, I'm really hating on people's work today. 

Edited by Promit

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MJP    19791

Yeah it's pretty nice. biggrin.png

Like most modern GPU's there's plenty of ALU available while you're waiting for reads from memory, and complex BRDF's are a pretty straightforward way to take advantage of that.

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FreneticPonE    3293

Yeah it's pretty nice. biggrin.png

Like most modern GPU's there's plenty of ALU available while you're waiting for reads from memory, and complex BRDF's are a pretty straightforward way to take advantage of that.

 

What are you guys doing for indirect specular?

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David Neubelt    866

 

Yeah it's pretty nice. biggrin.png

Like most modern GPU's there's plenty of ALU available while you're waiting for reads from memory, and complex BRDF's are a pretty straightforward way to take advantage of that.

 

What are you guys doing for indirect specular?

 

 

There are details in the course notes but specular probes.

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Promit    13246

I really don't love the specular probe thing, but I adore IBL and it seems like specular probes are the closest we're going to get in production real-time in the near future. I would like to see more work on that front though... the stuff out there still feels so hacked.

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MJP    19791

Yeah I'm not a fan of the probes either. You can setup cases where they work fairly well, but the standard methods for pre-integrating the specular BRDF will result in a very large error at the grazing angles. And then of course there's all of the standard issues with placement, blending between probes, incorrect parallax, memory usage, and so on which make them very difficult to work with both for artists and programmers. We've been researching alternatives, but I'm not sure if we'll come up with something in the near future. I'd been kinda hoping that someone else would have a cool idea in this area, but so far I haven't heard of anything outside of the voxel cone-tracing stuff.

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davepermen    1047

One of the papers that caught my eye this year in a bad way was the pre-computed cloth simulation. Essentially they took a (small) set of known character animations, put a cloak on the character, and precomputed every potential pose for the cloth and saved it in some kind of compressed 70 MB graph structure. Their proposal is that instead of trying to run cloth at runtime, you do it offline (4500 hours for this, if memory serves) and look up the results in the structure.

 

The paper tries to pitch this for upcoming gen real-time, which I find comical. The set of animations is small, the data is enormous to be traversing at runtime, and betting memory against compute power when GPU compute is coming fully into its own is tone-deaf at best -- if not completely insane. (Nevermind the implications to a production pipeline when the animation requires several thousand hours to regenerate.) While the technical aspects of the work may be well done, I really hate the core idea of this work and IMO it's a good example of bad academic work being pitched to industry.

 

part of my mind went towards "how about for mobile?". but then, nah.. i really think it's the wrong approach. still, the datastructure might have some interesting information in it.

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FreneticPonE    3293

Yeah I'm not a fan of the probes either. You can setup cases where they work fairly well, but the standard methods for pre-integrating the specular BRDF will result in a very large error at the grazing angles. And then of course there's all of the standard issues with placement, blending between probes, incorrect parallax, memory usage, and so on which make them very difficult to work with both for artists and programmers. We've been researching alternatives, but I'm not sure if we'll come up with something in the near future. I'd been kinda hoping that someone else would have a cool idea in this area, but so far I haven't heard of anything outside of the voxel cone-tracing stuff.

 

Geomerics, a third party GI thing, had this video I stumbled across a while ago: vimeo.com/geomerics/review/60838484/d2817c3548 (doesn't want to embed) Maybe it's some environment probe hack, but it sure doesn't look like it.

 

It also reminds me of something Epic did. For their Samaritan demo they managed to have static occlusion of their impostor reflections pre-baked. I remember a blog post mentioning something about tracing against a point cloud, but if so I can't find what paper that was gleaned from. Still, while it was static only and in the demo only gave occlusion info, it wasn't an environment probe, was high resolution, worked with arbitrary materials, and was assumedly faster than voxel cone tracing (though that's just an assumption).

Edited by Frenetic Pony

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Hodgman    51344

It also reminds me of something Epic did. For their Samaritan demo they managed to have static occlusion of their impostor reflections pre-baked. I remember a blog post mentioning something about tracing against a point cloud, but if so I can't find what paper that was gleaned from. Still, while it was static only and in the demo only gave occlusion info, it wasn't an environment probe, was high resolution, worked with arbitrary materials, and was assumedly faster than voxel cone tracing (though that's just an assumption).

IIRC, they bake the scene geometry into a 3D signed distance field. Tracing rays though that kind of structure is very efficient, except in cases where you have a ray that comes close to a boundary, but doesn't quite touch it. In the case where a ray is travelling parallel to a surface's tangent, very close to it, it becomes extremely inefficient, but all other cases are pretty good...

(Again, IIRC:) They trace reflections against a global cube-map, and dozens of reflection quads (either hand-drawn textures, like the neon lights, or slices of geometry that have been captured with artist-placed ortho frustums), using that 3D geometry texture to deal with occlusions.

 

[edit]P.S. congrats on the awesome presentation and work MJP :D

Edited by Hodgman

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MJP    19791

I thought I had remembered someone telling me that Geomerics was generating cubemaps at runtime, but I have no particular insight into what they're doing these days. And Hodgman is correct, Epic was tracing signed distance fields to get static occlusion for the Samaritan demo, which they coupled with an even more expensive solution for allowing dynamics to occlude reflections on planar surfaces. I'm not sure if they're still doing that for UE4, since it sounds fairly expensive.

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LimeLaser    103

I was actually kinda moved by the Global Illumination with Radiance Regression Functions clip.  However, it appears scenes are static and have a huge number of vertices.  What do y'all think?

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Hodgman    51344

I was actually kinda moved by the Global Illumination with Radiance Regression Functions clip.  However, it appears scenes are static and have a huge number of vertices.  What do y'all think?

Yeah IIRC, it's a technique for dynamic relighting of static scenes (with a large precomutation step). For games with static environments and dynamic lighting, it may be useful...

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Chris_F    3030

 

I was actually kinda moved by the Global Illumination with Radiance Regression Functions clip.  However, it appears scenes are static and have a huge number of vertices.  What do y'all think?

Yeah IIRC, it's a technique for dynamic relighting of static scenes (with a large precomutation step). For games with static environments and dynamic lighting, it may be useful...

 

 

I just watched the video. It was impressive.

 

[b]Too[/b] impressive. What's the catch? blink.png

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Radikalizm    4807

 



 



I was actually kinda moved by the Global Illumination with Radiance Regression Functions clip.  However, it appears scenes are static and have a huge number of vertices.  What do y'all think?

Yeah IIRC, it's a technique for dynamic relighting of static scenes (with a large precomutation step). For games with static environments and dynamic lighting, it may be useful...

 

 

I just watched the video. It was impressive.

 

Too impressive. What's the catch? blink.png

 

 

I'd call the precomputation step and the static environment requirements a pretty big catch tbh.

While the results are very very nice, it's not exactly a 'cheap' method from what I can tell (although I have to admit I didn't check it out in depth)

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Chris_F    3030

I'm not sure I'd call pre-computation or static geometry much of a catch considering that light mapping already has those limitations.

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