[vtkusers] matrix rotation "jumps"

[Christopher.Moore at noaa.gov]

I found the problem with my matrix multiplication (after much gnashing of 
teeth):

I accidentally set the focal point of the light to (1,0,0) instead of 
(0,0,0), so when the light's _position_ came around the circle to (1,0,0) 
it was understandably confused.

Operator error: my apologies.

Thanks for all the help - you guys are great.

Chris

On Tue, 26 Oct 2004, Andrew Maclean wrote:

> What you are seeing is probably correct behavior. I suspect you are
> experiencing the dreaded "gimbal-lock".
> 
> for a solution, look at:
> "Real-Time Rendering"; T. Akenine-Möller, Eric Haines; 2ndEdn, A.K.Peters
> Ltd.
> In particular 3.3.2 Quaternions, Rotation from one vector to another. 
> 
> This may give you a way of doing it.   
> 
> -----Original Message-----
> From: Christopher.Moore at noaa.gov [mailto:Christopher.Moore at noaa.gov] 
> Sent: Tuesday, 26 October 2004 10:44
> To: vtkusers at vtk.org
> Subject: [vtkusers] matrix rotation "jumps"
> 
> ...
> 
> 
> 
>