The box effect can be eliminated by blurring/texture filtering when a voxel is larger than a pixel on the screen. Like this: http://www.youtube.com/watch?v=_CCZIBDt1uM
Another advantage is that triangles can't realy match the level of detail of millions of voxels in a single space, even with culling, traingle tiling doesn't look that nice.
Carmack doesn't realy care for special effects; he wants to enable designers and take work away from them. He said that in a Doom3 engine interview. The way that artists create detail in Rage (as shown by YouTube videos) is by making the detail on the fly.I'm wondering if he'll be using the a sparse voxel octree for ray traced rendering, or more just as an advanced LOD system for traditional rasterisation methods.
It would be great to have a good LOD culling/streaming technique for triangles, but that can't be used to create content in the world on-the-fly. Even in Crysis, the world editor is used for creating voxelized terrain on-the-fly. Crysis also has some way to smoothen all the rough voxels so they look nice while being very large.
So you mean voxel data being traingle-ized?I got the feeling that he meant the latter, which makes a fair bit of sense. Current techniques are seeing more and more decoupling of geometry and final image, so thinking of geometry as just triangles may no longer be required (especially with the latest graphics card power).
It is using one very large 'atlas' texture, as far as my knowledge about atlas texture goes. It is devided into two files. A diffuse data file and a normal map file. The file structure is broken down into tiles of 128*128 for fast and easy loading, but it's a large, single texture.As far as I'm aware, the ET:QW megatexture was a vastly simplified version of picking out what's needed on screen - I do something similar for terrain rendering, I believe - but Rage is quite a good deal more advanced (probably uses a texture atlas setup - what fun with texture filtering that is).
You might be correct in that ET:QW doesn't have the 'Google maps' zooming feature for more detail. That indeed is in Rage.
There has indeed been a whole lot of papers published on speeding up the trees.There was a siggraph paper by Jon Olick, but I can't access it now. Sadly, I only remember it now and never actually went through it properly in the first place. Data streaming and proper data structures, if designed properly, can also take advantage of parallel processing (tree structures are good at that).
I found an awfull lot of graphics papers, freely available on a dutch university website here: http://graphics.cs.kuleuven.be/index.php/publications
Realy interesting publications, even though the last onces are from 2010. Realy worth checking it out!
PS: And here's a paper on implementing perfect ray-tracing at breakneck speeds: http://www.cs.columbia.edu/~batty/misc/ERPT-report.pdf
PS2: An here is a video that demonstrates the speed difference with normal path tracing: http://www.youtube.com/watch?v=c7wTaW46gzA