Re: [rp-ml] dxf Representation

From: Markus Hitter <>
Date: Sun Apr 26 2009 - 21:47:22 EEST

Hello Jonathan

Am 26.04.2009 um 17:15 schrieb Jonathan Chertok (Universal Joint):

> Can anyone help me understand the nature of dxf representation -
> say vis-a-vis stl? Are triangles definitively described in dxf format?

I'm pretty sure DXF allows more graphics elements than just
triangles. STL is triangle-only.

> Does this depend on the software generating the dxf? On the quality
> of the code?

Yes, the quality of the representation of your geometry depends on
the quality of the software. Neither DXF nor STL make any rules about
how close a set of triangles fits specific needs.

> Does all software "pass off" the rendering for this quad to the
> graphics card and if so can there be a difference between what is
> described in the geometry and what is shown on my screen?

Now, triangles sent to a graphics card represent the actual geometry
often at a very much lower quality than what you'd typically need for
manufacturing. A graphics card, for example, doesn't care wether the
edges of two neighbouring triangles fit together or not. It's also
harmless to send thousands of unconnected primitives to a graphics
device - an RP machine would likely choke on such a quality and ask
for a single, closed solid.


- - - - - - - - - - - - - - - - - - -
Dipl. Ing. Markus Hitter
Received on Sun Apr 26 21:45:28 2009

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