igs to stl

From: Andre Dolenc (ado@cs.hut.fi)
Date: Mon Dec 04 1995 - 10:30:03 EET

Joseph DeGuglielmo writes:
> 1)Could someone briefly explain how this process works and what its
> limits are?
> 2)What systems are compatible and which are not?

Excuse me, but before one can answer such questions, we need to clarify
something about IGES. IGES permits one to represent a variety of geometrical

1. As pointed out by Mr. Todd, the IGES file may contain a wireframe.
   Wireframes are *ambiguous* and it is impossible to convert them to solids
   automatically. Even an experienced CAD operator may derive the wrong model
   without input from the designer.

2. It may contain a cloud of points. The problem, then, is in the domain of
   reverse engineering. There are specialized tools for this.

3. It may contain a set of cross-sections. If they represent, say, a medical
   model, then, again, there a specialized tools for this too.

4. It may contain a solid model represented as a Brep or CSG tree. Well, again,
   the technology for facetting a solid model is an old one in CAD and
   approximation theory.

5. It may contain a description of a surface model. There is a lot of
   literature on this one too.

And so on. As you can see, IGES can be used for several purposes, and there
is no single method to convert a generic IGES file to STL.

Regards, Andre'

Helsinki  University  of  Technology       voice/fax: +358-0-4513239/4513293
Institute  of  Industrial Automation          e-mail: ado@mail.cs.hut.fi
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