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Subject: 
Re: Dimensions of the parts
Newsgroups: 
lugnet.cad.dev
Date: 
Tue, 13 Apr 1999 18:12:01 GMT
Viewed: 
832 times
  
Leonardo Zide skrev i meddelandet
<3712B018.76665708@centroin.com.br>...

But how can the program know if a face from a piece is inside • another
piece ? I've been only testing for intersections between faces.



If any two corners of a (planar) face, from one brick, is on opposite
sides of a (planar) face of the other brick, they must be intersecting
(not completely true, of course, as you have to take the size of the
faces into consideration too).

But perhaps I misunderstood your question? Do you mean: how to find
out if (for example) a peg is inside a hole, and still no _faces_
intersect?

I suppose you could do it (perhaps with a little knowledge of _which_
pieces goes inside things) by testing one piece against a 'bounding
box' of the other one (Or, to get more precision, the 'convex hull' -
computationally heavy).

Or you could edit your pieces and add invisible faces over openings,
so you have a face to test against. One piece _completely_ enclosed by
another would still not be detected this way.

A good newsgroup for this kind of problem is
comp.graphics.algorithms - if you don't already read it take a look!

--
Anders Isaksson, Sweden
BlockCAD:  http://user.tninet.se/~hbh828t/proglego.htm
Gallery:   http://user.tninet.se/~hbh828t/gallery.htm



Message is in Reply To:
  Re: Dimensions of the parts
 
(...) But how can the program know if a face from a piece is inside another piece ? I've been only testing for intersections between faces. Leonardo (26 years ago, 13-Apr-99, to lugnet.cad.dev)

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