Then of course there are the problems with lighting, animation and so on.

You're right that lighting and animation are real problems with voxels. Animation in particular is pretty much impossible, which means you have to fall back to polygons for anything that moves or changes, which in modern games is a lot of stuff.

No no, I explicitly said "ahead of time". It's easy to determine what's on screen when you're about to render the frame, but you have to load every single object in memory because every single object is a "candidate" that may end up on the screen, you just don't know ahead of time. You can't cull the voxel tree, even though 99% of the voxel tree won't be used when rending a frame. So the memory overhead is immense.

Voxel trees don't make it easy to discard things that are far away at all, because there aren't any low-resolution objects that you can use for far-away objects. You have to load many objects in memory even when you use them to render just a pixel or two.

The polygon-based worlds we have today use various low-resolution models for when you view at a distance, and as you get closer the higher resolution models "pop in". This tech advertises that you have infinite detail and that there's no need for objects with different level of detail. This means that the complete point cloud of every object has to be loaded in memory and that's a very real problem and it's in complete contradiction to the claims made by the company that artists can create infinitely detailed worlds without having to worry about vertex counts or whatever. Artists have to compose their world out of re-usable high-detail objects or the sparse voxel octree will be way too large. This means the artists will be much more constrained than they are today, not less.

My understanding is that the problem is that there's just too much stuff that you have to keep in memory if you don't use LoD to distinguish between nearby and far away objects.

Consider this screenshot from rage: http://pcmedia.ign.com/pc/image/article/116/1162072/rage-201...

What are you going to cull? There's just too much stuff to load in memory. Too much stuff that actually ends up on your screen. Too much point cloud data. Now games use low resolution models and prerendered billboards for far away objects. With a voxel octree you're just SOL, no matter how clever your spatial optimizations.

Unless hard drives (or SSDs) become a few orders of magnitude faster I don't see how the data can be fetched from disk quickly enough.

But if they still need to use 'traditional' techniques like LoD, rendering at various resolutions, etc, then the complexity and running speed can't be all that much faster than a traditional approach. The way I've been reading these articles is that somehow he's got a very fast method of deciding which voxels to show, without any pre-processing or optimisation - just brute force. I'm curious to see the first demo they'll come up with, especially since they only now seem to be at a point where they can render without shading, animation etc, and they make it seem as if those are just implementation details that can be added on an afternoon. We'll see.

[1] http://www.flipcode.com/archives/Realtime_Voxel_Landscape_En...

[2] http://www.youtube.com/watch?v=_CCZIBDt1uM

Part of the point cloud needs to move for animation, which involves re-indexing at least part of the world. Doing this once per frame is probably far too expensive (at least currently), which is why animation doesn't feature in their videos.

That doesn't mean this technology should be dismissed; most world data in 3D scene graphs is static, so it does have applications. I don't see it overtaking rasterised graphics entirely, but I think there is value in it.

I'm not an expert either, so take my comment with a healthy bucket of salt.

Edit: They claim in the article to have devised an approach that no-one else has come up with, and they give this as the reason why no-one else is doing something similar.

With voxels, you'd have to recompute all the voxels of the object on a 3d grid. Also there are issues with ragged boundaries, which can be prevented by using antialiasing, but which is probably trickier (=more computationally intensive) than in 2D...

The displacement of the voxels can also be done with a simple matrix transformation, as far as I see it; same like you'd do for the nodes in a 3d model, same as you'd do it with a 'traditional' 3d pipeline (OpenGL/DirectX) - unless I'm behind the curve and animation itself is done on the GPU nowadays, but I don't think it is.

Ragged boundaries wouldn't be an issue as long as there are enough voxels. What I understand, that's the whole point - you just have lots and lots of voxels, at a much finer resolution than you'd ever want to render at, so that you just (by brute force) render once without having to worry about anti-aliasing, gaps between planes etc.

Yes, but the point is that you have to displace much more voxels than you'd have to displace vertices otherwise. Vertices are only on the boundaries of the object (and quite sparsely at that if you use normal mapping shaders etc wisely) but voxels fill the entire object densely...

I was under the impression that they fill the object's hull

EDIT: If you are spekaing about preprocessing data - yes - you can rotate as much as you want, the only problem will be that object instanced 1000 times with different orientation/scale will take 1000 times more memory than object instanced 1000 times with the same orientation/scale. With polygons there is no difference.

But yeah, the amount of data you'd have to work on would be much greater, but the way I interpret all of this is that he's found algos to do that very fast, regardless of whether it's a lot of data.

Supposing this is legit, I'm cautiously optimistic, homie has probably uncovered some very novel techniques that allow the granular level of detail you couldn't do before with voxels, with optimizations that don't require GPU .. this is pretty amazing.

as far as i can tell their voxel tech is just for non-moving objects like the landscape, buildings, etc. animated and moving actors are still rendered as polygons and blended into the scene (according to the article, this already works to a certain degree, but they weren't able to give a live demo, just a video).