RE: [Algorithms] Massive spaces

[Graham S. R. <gr...@se...>]

Sam,

You should *definitely* look at the Hayden Planetarium work, done by

See this link: http://www.sgi.com/features/2000/feb/hayden/

I've seen this application running, at SIGGRAPH 99. It is *really*
impressive. It is similar to what you're talking about, but it models the
entire galaxy not just a solar system. And it doesn't let you zoom in and
see the surface details of a planet. (You can fly through volumetric
nebulae, though, and zoom in to see how constellations look in 3D.)
Graphics-wise, consumer gaming hardware is coming darned close to the
capability of  the 7-graphics-pipe Onyx2 system they use (with a capability
of a maximum of 70 million polys/second), but they do have 28 processors to
generate stars, stream textures from disk, etc.

1/100000 meter? Whoa. You'd want an awesome amount of texture storage, very
very fast disk access, and smooth, seamless texture
zooming/mipmapping/cliptexturing.

Graham Rhodes
  -----Original Message-----
  From: gda...@li...
[mailto:gda...@li...]On Behalf Of Sam Kuhn
  Sent: Sunday, August 20, 2000 9:33 PM
  To: gda...@li...
  Subject: [Algorithms] Massive spaces


  Hey,

  I've got a little mind game for you lot.

  Say you needed to render an entire solar system, in which you can zoom
down to a planet surface and see detail of about 1/100000 meter, or shoot
over to the sun and see the same sort of detail. There are a couple of
immediate problems:

  You would need need an enormous view volume (what say 20 lightyears big)
which gives an appauling zbuffer resolution.
  So whats are you to do? Render the distant objects closer than they
actually are (i.e. at the far end of a planet-sized view volume) and scale
them down accordingly?. This surely would give incorrect parralax between
the distant objects

  Also you need the planets to be of enormous size so that the front
clipping plane doesn't cut through the planets fine detail when you are in
very close (lets say an ant view for example). Which again buggers the
zbuffer, since you're using a planet sized view volume.

  Any ideas?

  Regards,

  Sam.