Kastrullo skrev:Perhaps you’ve seen the videos about some groundbreaking “unlimited detail” rendering technology? If not, check it out here, then get back to this post:
http://www.youtube.com/watch?v=00gAbgBu8R4
Well, it is a scam.
They made a voxel renderer, probably based on sparse voxel octrees. That’s cool and all, but.. To quote the video, the island in the video is one km^2. Let’s assume a modest island height of just eight meters, and we end up with 0.008 km^3. At 64 atoms per cubic millimeter (four per millimeter), that is a total of 512 000 000 000 000 000 atoms. If each voxel is made up of one byte of data, that is a total of 512 petabytes of information, or about 170 000 three-terrabyte harddrives full of information. In reality, you will need way more than just one byte of data per voxel to do colors and lighting, and the island is probably way taller than just eight meters, so that estimate is very optimistic.
So obviously, it’s not made up of that many unique voxels.
In the video, you can make up loads of repeated structured, all roughly the same size. Sparse voxel octrees work great for this, as you don’t need to have unique data in each leaf node, but can reference the same data repeatedly (at fixed intervals) with great speed and memory efficiency. This explains how they can have that much data, but it also shows one of the biggest weaknesses of their engine.
Another weakness is that voxels are horrible for doing animation, because there is no current fast algorithms for deforming a voxel cloud based on a skeletal mesh, and if you do keyframe animation, you end up with a LOT of data. It’s possible to rotate, scale and translate individual chunks of voxel data to do simple animation (imagine one chunk for the upper arm, one for the lower, one for the torso, and so on), but it’s not going to look as nice as polygon based animated characters do.
It’s a very pretty and very impressive piece of technology, but they’re carefully avoiding to mention any of the drawbacks, and they’re pretending like what they’re doing is something new and impressive. In reality, it’s been done several times before.
There’s the very impressive looking Atomontage Engine:
http://www.youtube.com/watch?v=Gshc8GMTa1Y
Ken Silverman (the guy who wrote the Build engine, used in Duke Nukem 3D) has been working on a voxel engine called Voxlap, which is the basis for Voxelstein 3d:
http://www.youtube.com/watch?v=oB1eMC9Jdsw
And there’s more:
http://www.youtube.com/watch?v=xUe4ofdz5oI http://www.youtube.com/watch?v=lEHIUC4LNFE http://www.youtube.com/watch?v=Zl9CiGJiZuc
They’re hyping this as something new and revolutionary because they want funding. It’s a scam. Don’t get excited.
Or, more correctly, get excited about voxels, but not about the snake oil salesmen.