Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!hubcap!bo
From: bo@hubcap.clemson.edu (Bo Slaughter)
Newsgroups: comp.graphics
Subject: 3-D Rotation Algorithm
Message-ID: <6734@hubcap.clemson.edu>
Date: 11 Oct 89 02:19:01 GMT
Organization: Clemson University, Clemson, SC
Lines: 18



I have written a program in Turbo Pascal to take a simple line drawing
and rotate in any of the 3 demensions. The "drawing" consists of a
series of lines with X,Y,Z coordinates, which my program then can rotate
using the simple formula (and variations thereof):

  X'=X*cos(THETA)-Y*sin(THETA)
  Y'=X*sin(THETA)+Y*cos(THETA) 

My problem is that this is extremely slow for any medium sized drawing
(32 points took over a second).  Does anyone know of, or have, an
algorithm that could do the same calculations, without all the mucking
about with slow foating point calculations (No, I don't have a math
coprocessor).

Thanks,
Bo Slaughter