Zero installation at the cost of 10x worse performance is a worthwhile tradeoff for websites, but not for games or other 3D-heavy applications. That won't change as computers get faster, because native apps get faster too. Web 3D won't be widely adopted until it can close the performance gap. The OP makes that problem worse, not better. Hence my negativity.

Bullshit that web 3d won't be adopted. It already is! Google maps uses web 3d pretty heavily already, and it's a perfect example of this.

But even if i concede that point, i still don't agree. Who are you to say that this doesn't solve any problems?

Say for example a website that wants to include something so you can view a product in 3d and be able to move it around and inspect it.

That's not something i want to have to download a full desktop program for and give it access to god knows what on my machine for, but it's something i'd love to have to see a 3d render of something to get an idea for it's size/shape/other features.

OP isn't even marketing it as a library for "games or other 3D-heavy applications", he's marketing it as a really easy way to get some 3D rendering in the browser.

For what it's worth, I agree that the web needs something like WebGL to cover the Flash use cases (animated ads and casual games).

Not sure why you need voxel.css, though. When would you use it instead of http://www.marmoset.co/viewer ?

No one's claiming it has any practical use case, this is really just a toy.

Though, one use case might be to have a 3D environment where in-game menus are made with the DOM. Maybe in a virtual reality thing, or a rotating cube interface: http://ux.stackexchange.com/questions/11229/is-this-rotating...