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 CAD / Development / 7097
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Subject: 
Re: Parts as volumes (instead of surfaces)
Newsgroups: 
lugnet.cad.dev.org.ldraw, lugnet.cad.dev
Followup-To: 
lugnet.cad.dev
Date: 
Sun, 7 Apr 2002 15:21:52 GMT
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68 times
  
[ XFUT lugnet.cad.dev ]

Damien Guichard wrote:

It has been said that, with ldraw parts, we have the geometry of TLG bricks.
This is rather optimistic. Because geometry would be CSG descriptions that
allow much more (although slower) than quads and triangles. CSG descriptions
allow part collision detection.

What's "CSG descriptions"?

Thinking about BFC statements I realised they also allow collision detection.
The prerequisite is having convex parts.

But they aren't (as you also write).

Still, you are probably correct that BFC information in the
LDraw parts can be used for collision detection.

Anyway, the remaining problem is that most (if not all, including Brick 2 x
4) ldraw parts are not convex but concave. Is there any simply mean to
extend BFC with metacommands that split ldraw parts in convex subpart? Does
the topic deserve the effort? Any interest at all? Just an idea to see what
reply.

I think it deserves further consideration.

Jacob
--
No trees were killed in the sending of this message.
However a large number of electrons were terribly
inconvenienced.



Message is in Reply To:
  Parts as volumes (instead of surfaces)
 
It has been said that, with ldraw parts, we have the geometry of TLG bricks. This is rather optimistic. Because geometry would be CSG descriptions that allow much more (although slower) than quads and triangles. CSG descriptions allow part collision (...) (23 years ago, 6-Apr-02, to lugnet.cad.dev.org.ldraw)

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