Lets talk about possible unconventional methods....

[royalestel]

I was thinking that in the future we could use an isometric voxel array to represent molecular interactions in the near LOD and that distant LODs would be polygon renderings. I know that LucasArts is using voxels for explosion smoke simulation.

I also think that with HDR rendering, we could now reorganize our engines to put more resources towards rendering high-contrast boundaries, which are areas the eye is naturally drawn to.

As long as some grain is rendered on top of everything, you could even skip rendering low contrast areas (or interpolate them) for several frames with the viewer not even noticing.

And I still think we could take a page from the old flight simulation handbook and do a better job of fading in our LOD model changes. Those sudden pops really are jarring.

I know that pilots found geomorphing to be objectionable when dealing with terrain, but I think on moving models, it would also be an improvement over LOD 'pop'.

We'll probably also end up using Normal maps or one of the newer approximations to represent anisotropic surfaces like brushed metal. That is an area with definite room for improvement as far as LOD goes (normal maps, I mean). You can't average out a normal map without serious problems!

That's what I'm thinking.

What's an HOS representation?

 

[Shifty Geezer]

I was thinking that in the future we could use an isometric voxel array to represent molecular interactions in the near LOD and that distant LODs would be polygon renderings. I know that LucasArts is using voxels for explosion smoke simulation.

Actually LucasArts are using Digital Molecular Matter that represents everything in volumes and is transformed to polygons with LOD in realtime.

Automatic Level Of Detail (LOD)
Because we store a volumetric archetype format of the object, DMM objects are not limited by mesh control point limitations when attempting to decimate meshes for different levels of detail. Each LOD version is built by traversing the DMM data structure to whatever level of detail is desired. This yields a natural tesselation of the final surface mesh that is just as accurate or much so than a hand-drawn one.

http://www.pixeluxentertainment.com/tech.htm

What's an HOS representation?

High Order Surface. Basically a surface defined by curved edges (think Beizer curves in a vector graphics program) instead of flat edges. Thus you can define a sphere as a perfect sphere instead of needing lots of triangles to approximate the smooth curve. If using HOS, at rendertime you need to tessellate the curved surface into triangles for the GPU to render. There's the potential for excellent LOD, tessellating only the part of a curve you can see at a resolution appropriate for distance from camera. If this system is perfected, the current polygon rates of GPUs ought to be enough to provide 'perfect' polygonal graphics, being (more than) capable of one polygon per pixel.

 

[fearsomepirate]

The reason polygons have stuck around so long is:

a) Mathematically, any 3D solid can be approximated arbitrarily well with polygons. This makes polygons very versatile. Of course, polygon approximations also converge more slowly than just about any other type you might think of (Bezier patches, etc), so that means you have to use a lot of them. But that's not too bad because...

b) The mathematical manipulation of triangles is about as simple as it gets. Whether computing surface normals, shading, or what have you, computations involving triangles are extremely simple, thus very fast.

They're just so fast and simple that I don't see them ever being replaced any time soon. Perhaps used in conjunction with other things (as pointed out, they're not good for smoke), but for your basic geometry, they're hard to beat.

 

[royalestel]

Actually LucasArts are using Digital Molecular Matter that represents everything in volumes and is transformed to polygons with LOD in realtime.

That looks like what I was thinking of. I suppose when I think of voxels I think of 3d bits of information, not just color. I had an acquaintance who got hired on there to work on such a subsystem and he described it as "pretty much voxels".
Anyhow, isometric arrays: still could use those, I think. I was trying to convince him to push for that when he left. Even gave him a model of what a representation of a single element in the array might look like if we assumed all "voxels" were inflated so they filled space completely.

Looked a bit like origami.

Anyhow, I know I'm rambling now. It's cool to see the things I dream up being worked through and created by truly talented and hardworking folks.

 

[Shifty Geezer]

That looks like what I was thinking of. I suppose when I think of voxels I think of 3d bits of information, not just color.

That's how I consider them. A pixel is a rectangular block of attributes in 2D space with colour and whatever other attributes you want like depth, normal, UV coord. A voxel is a cuboid block in 3D space with whatever attributes, like colour, translucency, density. You can pile on the attributes for each spacial coordinate as needed. The big problem with the straight forward dumb method is storage and BW. If you have a clever way of defining volumes and pointwise properties per 3D coordinate very efficiently, which I guess DMM has, it could be a very good system to introduce now we have lots of processing power. And the demos of DMM have been pretty impressive.

 

[Simon F]

That's how I consider them. A pixel is a rectangular block of attributes in 2D space

Not according to Alvy Ray Smith of NYIT, LucasFilm and Pixar fame.

A Pixel Is Not A Little Square, A Pixel Is Not A Little Square, A Pixel Is Not A Little Square...

:smile:

 

[royalestel]

A voxel is a cuboid block in 3D space

It can also be any space-filling 3d array. Mine are more hexagonal prisms, each side is a parrallelogram, total of 12 sides. If you look up "Yoshi's Puzzle" there's a picture I tried posting that is the exact shape I'm thinking of.

And it turns out, some hexagonal addressing schemes are very well suited to LOD rendering.

 

[Shifty Geezer]

A voxel is a cuboid block in 3D space

It can also be any space-filling 3d array. Mine are more hexagonal prisms, each side is a parrallelogram, total of 12 sides. If you look up "Yoshi's Puzzle" there's a picture I tried posting that is the exact shape I'm thinking of.

And it turns out, some hexagonal addressing schemes are very well suited to LOD rendering.

That's a good idea I hadn't considered. Although my choice of geometry was only as explanation to what a voxel is in terms of data structure! It's a point that can have whatever values you want associated, rather than being limited to just storing a colour value.