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Subject: 
Re: Seemingly insane poly counts in official games - how?
Newsgroups: 
lugnet.cad
Date: 
Wed, 22 Jun 2005 17:08:21 GMT
Viewed: 
2010 times
  
In lugnet.cad, Steve Bliss wrote:
   In lugnet.cad, Tim McSweeney wrote:
   In theory it should be possible (although not necessarily easy) to do some of this automatically for Ldraw models.

In practice however the hairiness of the Ldraw dataset (BFC issues and the fact that parts weren’t authored with this sort of brutality in mind) make it much more difficult than it should be.

One way to do this would be project rays through a model, selecting rays with random angles. Keep track of which polygons in the model initially (and finally) intersect the ray -- these polygons are visible. Repeat this process for enough rays, and you’ll have a (fairly accurate) list of visible polygons. All other polygons aren’t visible and can be eliminated.

This process probably wouldn’t be fast enough for interactive programs -- but preprocessing a fixed-model for use in a game would be very do-able.


Yeah, I considered that, The other way I thought of doing it is to create some sort of projection volume for each tri (Basically the halfspace stretching from the front face of the tri out to infinity), then clip that by the other tri’s in the scene. If after doing the whole list part of the original volume still reaches to infinity then that tri would be visible from outside the model.

All theory though.

Tim.



Message has 2 Replies:
  Re: Seemingly insane poly counts in official games - how?
 
If you were to couple those routines with the script available here, and Blender's power: (2 URLs) You would have a relatively easy way to make CG Lego sequences. It could lead to some really cool stuff, perhaps more things in the vein of the (...) (19 years ago, 22-Jun-05, to lugnet.cad, FTX)
  Re: Seemingly insane poly counts in official games - how?
 
I am wondering whether you could do this: Pass a plane through a model along the X axis. Keep track of which polys intersect the plane. If these intersections then intersect with each other, they will form 2D shapes on the plane. If any of these (...) (19 years ago, 7-Jul-05, to lugnet.cad)

Message is in Reply To:
  Re: Seemingly insane poly counts in official games - how?
 
(...) One way to do this would be project rays through a model, selecting rays with random angles. Keep track of which polygons in the model initially (and finally) intersect the ray -- these polygons are visible. Repeat this process for enough (...) (19 years ago, 22-Jun-05, to lugnet.cad, FTX)

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