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Date: 24 Sep 91 20:55:50 GMT
From: bouma@purdue.edu  (William J. Bouma)
Subject: Re: Request for robotic simulation assistance
Message-ID: <16220@ector.cs.purdue.edu>
List-Id: <comp.lang.ada>

In article <802@ajpo.sei.cmu.edu> wellerd@ajpo.sei.cmu.edu (David Weller) write
s:
>Is there a more convenient form for collision detection between
>objects in a graphical environment?  Additionally, our approach rests
>heavily on sequential forms -- there is no tasking in our simple
>model.  Is it prudent to build a graphical simulation of objects as
>"tasks", particularly when real-time detection of collision (or 
>collision avoidance) amongst all objects is important?  There is also
>the outside chance that our simulation will work in a distributed 
>environment -- will this impact design decisions?

  Convenient in what sense?  It sounds like you want someone to tell you
  there is a way to detect collision points without intersecting every
  pair of objects?  How could that be possible?  If objects are moving
  along preset paths you can sweep the time-space volumes and determine
  where these intersect to determine first time of collision.  Then you
  don't have to worry about the objects until your simulation progresses
  to that time.  But any interesting simulation will not have all objects
  moving along preset paths!

  Is your concern that the speed of this collision check is too slow?  If
  you use polyhedral objects, you can look at the Brep-Index methods of
  Dr. George Vanecek. (references if interested)  This yeilds a quick
  way of classifying the edges of one object against another.  You can
  analyze the classifications of all the edges to determine which entities
  of the two objects are in contact. 

  I am not sure what you are talking about when you say "tasking"?  What
  does "a graphical simulation of objects as 'tasks'" mean?

  Also, if you are doing this stuff in "real-time" you must have a bank of 
  super computers to run on!

  If you wish to distribute the work, obviously you can at least do the
  pairwise intersections in parallel.
-- 
Bill <bouma@cs.purdue.edu> 

    "The decision could easily be made by a computer." -- Dr. Strangelove