BTW, perhaps I'm limited in my understanding but I acquire info with my senses and process it using my brain and what I see...
...is that there's nothing besides this island, which is admittedly bigger than atomontage but limited nonetheless. So, when he's talking about being unlimited - aka infinite - surely he's not talking about "infinitely large" but rather "infinitely small". As a start.
They've shown a bunch of other older demos which were slightly more varied in the blocks used, but those instead lacked much of the quality... so they just traded one thing for another. And so far, everything we've seen that would be indicators of memory usage have been terribly bad (few overly reused blocks, non-shaded materials, etc). Worse than that it even seems as if they are constrained to a grid, because every single demo they've ever shown has been built from prefab tiles as far as I've been able to tell.
However, it should be important to note that the size of the island they show is in most likelihood meaningless, they could probably with ease make it... A MILLION TIMES... larger without any issues, that is meant to be the strength of the algorithm... however, they could not add more unique models to make any use of it.
And what really strikes me as strange is why they are still running it on only 1 core after all these years, it should be pretty much trivial to utilize all the cores (and remove any chance of gameplay!). I'm curious how memory performance and bandwidth works out for this, now I'm far from an expert on this, but it really seems as if that could be a potentially huge issue to overcome if it indeed is an issue (much like it is an issue with raytracing).
But really, it all falls flat in theory for me. Textures and geometries today consume enough storage and memory as it is, we couldn't simply double that today and expect everything to run well. So, now consider that reusing textures over and over like we do today is very efficient... even storing color data as textures is efficient, it allows for compression and compositing multiple textures to seemingly make up quality from thin air. Triangle geometry is efficient, you can store enormous landscapes as dirt cheap (even compressed) heightmaps.
Now, consider what UD is doing:
They apply the texture individually to each voxel... so there is no texture reuse at all, it becomes harder to compress the color data
They break up the geometry into individual voxels... so a single triangle becomes a lot of voxels
So, let's for the sake of the argument say that, they have somehow managed to come up with a compression algorithm that takes all these voxels and manages to compress them down to the size of the original polygonal model. Great... right? Well, I would argue that no, it doesn't really matter all that much... because it all comes back to the texture issue. With polygons, we can make a statue that uses 2 textures, then make a 100 more statues using the same textures. In UD, every single object has its own unique "texture"... and note that the same is true for terrain. You can no longer reuse that grass texture over and over, or use a dirt cheap heightmap to represent hundreds of kilometers terrain... instead you now have to represent each triangle and texture by hundreds and hundreds of small voxels.
There is simply no way they could achieve the storage efficiency we enjoy today, even if they use every imaginable cheat and use 3D texture materials and all kinds of tricks... it will never be nearly as storage efficient as polygonal geometry and textures, it simply can't. Or am I missing something?
And like all good things, they are not good things unless they also work in practical circumstances, it's "easy" enough for nVidia and 3DMark to whip up impressive and carefully tweaked demos, applying it in games is a very very different thing