@Kraken: You asked for it:
http://www.youtube.com/watch?v=hapCuhAs1nA&t=17m13sText transcript below:
Okay, for one thing, I think it’s important to separate the notion of infinite detail and Voxels. You can have Voxels [that are not infinitely detailed] because many of the Voxel engines that I’ve written have been at finite coarse levels of detail. The fact that you can instance detail in [Voxels]... in may ways it sounds awesomely cool: “infinite detail,” but if we look at all of the trends that we’ve been doing and Rage epitomizes in many ways, procedurally generated detail is usually not what you want. This has been an argument going back decades: “now is the year of procedurally generated textures and geometry.” We’ve heard that for a decade and it never has come true. What has won is being able to manage the real data that we want. Procedural-ism is really just a truly crappy form of data compression. You know, you have the data that you really want, and procedural-ism makes you something that might resemble what you really want, but it’s a form of extraordinarily lossy data compression that lets you produce something there.
And that really is the problem with the voxels. Infinitive detail is basically procedural-ism and you can do that with polygons, voxels, atoms, splats, whatever. They are tied together now with people talking about the recent demo that came out, but they are really orthogonal topics. I don’t think the notion of infinite detail is actually all that important. It is more important to be able to get the broad strokes of the artistic vision in there, and if you take uninspired content and look at it at the molecular level, it is still uninspired content. It’s not really going to make a big difference. What is potentially useful about voxels is that it allow you to access them in a certain way that may be more efficient than say a rise pipeline of dicing polygons, doing displacement mapping, and things like that. They are both ways to give huge amounts of geometric detail, which is obviously the next frontier after we uniquely texture everything. We want to uniquely “geometrify” everything. We all want to go there, but it’s also important to realize that I was showing MegaTexture demos five years ago. It took five years for it to turn into a production quality game, and you could make a cool, flashy demo of like “look, isn’t this amazing, we can stamp down stuff and everything looks totally different? There’s no tiling, and we can use procedural information to generate all of this,” but there is a huge amount of work that goes into building a robust production quality system that you can build real game worlds with.
I’ve revisited voxels at least a half dozen times in my career, and they’ve never quite won. I am confident in saying now that ray tracing of some form will eventually win because there are too many things that we’ve suffered with rasterization for, especially for shadows and environment mapping. We live with hacks that ray tracing can let us do much better. For years I was thinking that traditional analytical ray tracing intersecting with an analytic primitive couldn’t possibly be the right solution, and it would have to be something like voxels or metaballs or something. I’m less certain of that now because the analytic tracing is closer than I thought it would be. I think it’s an interesting battle between potentially ray tracing into dense polygonal geometry versus ray tracing into voxels and things like that. The appeal of voxels, like bitmaps, [is that] a lot of things can be done with filtering operations. You can stream more things in and there is still very definitely appeals about that. You start to look at them as little light field transformers rather than hard surfaces that you bounce things off of. I still wouldn’t say that the smart money is on voxels because lots of smart people have been trying it for a long time. It’s possible now with our current, modern generation graphics cards to do incredible full screen voxel rendering into hyper-detailed environments, and especially as we look towards the next generation I’m sure some people would take a stab at it. I think it’s less likely to be something that is a corner stone of a top-of-the-line triple A title. It’s in the mix but not a forgone conclusion right now.