Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!tellab5!fayne
From: fayne@tellab5.TELLABS.COM (Jeffrey Fayne)
Newsgroups: comp.graphics
Subject: Re: 3D Animation Source Code Wanted
Keywords: 3D animation C code wireframe
Message-ID: <1920@tellab5.TELLABS.COM>
Date: 3 Jan 90 13:39:20 GMT
References: <9170@cbmvax.commodore.com> <21550@mimsy.umd.edu> <21561@mimsy.umd.edu> <21562@mimsy.umd.edu> <9182@cbmvax.commodore.com> <1990Jan2.224220.4136@ux1.cso.uiuc.edu>
Reply-To: fayne@tellab5.UUCP (Jeffrey Fayne)
Organization: Tellabs, Inc. Lisle IL
Lines: 50

In article <1990Jan2.224220.4136@ux1.cso.uiuc.edu> mjw06513@uxa.cso.uiuc.edu (Mary J Winters) writes:
>

                              [misc deleted]

>
>I would very much like to learn the techniques used to produce fast 3D
>animation of wireframe objects. I assume it is done using only integer
>math, with optimization techniques such as multiplication/division replaced
>by shifts, lookup tables for trig/transcendental functions, etc. Can anyone
>point me toward a good source of information on these and similar topics?
>Any information (book titles, anon. ftp sources for code, etc.) would be
>greatly appreciated. 
>


I also would like more information.  I've already skimmed thru the books
recommended on the weekly posting, while of great help, they are a little
heavy on theory and very light on application. 
The biggest problem I'm having is that all the rotation texts I've seen
assume that the rotations are based on the viewers viewpoint and not the
objects (ie.  I can rotate an object (say an airplane with the nose
pointing away from the viewer) and apply rotations (yaw, roll and pitch)
that look correct only from this perspective. As soon as the object is
rotated (say 90 degrees with the nose pointing to the positive X axis)
the rotations are incorrect for the object but still correct from the viewer's
perspective(plane: pitch rotations look like rolls, roll rotations
look like pitch, while from the viewer's perspective the object is still
rotated the same).  The question I have is should another sort of rotation
sequence be applied to the object (or the viewer) or should I take the 
'brute-force' approach (if yaw == 90 and roll is desired then pitch instead)
?   Any pointers to info would be appreciated.

				Jeff


 
to organise my thoughts, I'm going to post



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