Path: utzoo!utgpu!news-server.csri.toronto.edu!me!sun
Newsgroups: comp.graphics
From: sun@me.utoronto.ca (Andy Sun Anu-guest)
Subject: aspect ratio in IGES
Message-ID: <90Jun12.154411edt.19557@me.utoronto.ca>
Reply-To: sun@hammer.me.UUCP (Andy Sun Anu-guest)
Organization: University of Toronto, Department of Mechanical Engineering
Date: 12 Jun 90 19:44:23 GMT

I tried to port an IGES file generated by SDRC I-DEAS on a SUN SPARCstation
to a PC and read in by AutoCAD Release 10. Except for a few "supported
entities", AutoCAD gladly inhaled the 1+ Mb IGES file into it and
displays the image on the screen (though it takes forever to regenerate
on a PS/2 Model 50Z). The problem is that the image is being turned
up-side-down and is highly distorted (compressed in the y direction by almost
a factor of 2). It looks to me that it is because of the screen aspect
ratio difference. I haven't checked the IGES specs yet, but it doesn't
make sense to me that a device dependent parameter is incorporated into
this "neutral file". I would think IGES will store the absolute lengths
of any lines, etc. and should be independent of the screen resolution.
Anyone knows the reason for this or wants to correct my misconception on IGES?

Andy

_______________________________________________________________________________
Andy Sun                            | Internet: sun@me.utoronto.ca
University of Toronto, Canada       | UUCP    : ...!utai!me!sun
Dept. of Mechanical Engineering     | BITNET  : sun@me.utoronto.BITNET