[vtkusers] Camera Dollying

[Gharrison9 at aol.com]

I have a project where I am using the cursor keys and Page Up/Down to do 
camera yaw, pitch, and dolly. The comments for Dolly in vtkCamera is

  // Description:
  // Move the position of the camera along the direction of projection. 
Moving
  // towards the focal point (e.g., greater than 1) is a dolly-in, moving 
away 
  // from the focal point (e.g., less than 1) is a dolly-out.
  void Dolly(double distance);

Also, according to the description of Dolly in the VTK book (2nd edition) 
Dollying in and out should move the camer's positon along the direction of 
the focal point. 

I take it that the focal point remains the same while the distance from it 
and the camera gets shorter or longer (dollying in or out).

So, If I want to preserve my focal length, do I have to change both the focal 
point and the position of the camera as it moves throughout three space?

Thanks friends!

George


George C. Harrison Professor of Computer Science
Norfolk State University
Telephone: 757-823-8654
Fax: 757-823-9229
email: gharrison9 at aol.com
or gcharrison at nsu.edu (same difference..)
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