I realized after I sent this that my ramblings are probably not helpful.
Sorry if this created more confusion than clarity.

dave

----- Original Message -----
From: "David Yazel" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, May 11, 2002 2:22 PM
Subject: Re: [JAVA3D] Zoom without moving the Viewpoint


Thats a good question.  To answer it you need to consider what a view is
really doing.  It is taking an image plate (your screen) and transforming
the 3d geometry so that it renders in the 2d space, perfectly matching your
screen, basically flattening the 3d.  This transformation uses a projection
policy to determine they type of transformation that is happening.  But if
your view is at position x,y,z and you are viewing a point at x'y'z' then
the distance from the view to the point is fastored into the "depth" of the
image.  The width of the object you are looking at in virtual units will map
to some number of pixels on your screen.  To zoom you are shortening the
distance between the object and the view. This means that other objects at
the edges of your scene leave the field of view and are lost.  There are
only two ways to shorten the distance between the view and the object.
Either move the object or move the view.  Now "moving the view" means
different things to different people.  You could have the view at a certain
translation, but apply a scaling to the view.  This actually does "move the
view" since the mapping from the image plate to the object changes, but it
still resides in the same translated state.  I have never tried to scale a
view... but technically it should work.

Dave Yazel
http://www.magicosm.net/




----- Original Message -----
From: "Pereira Sieso, Rafael" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, May 11, 2002 12:37 PM
Subject: [JAVA3D] Zoom without moving the Viewpoint


Hello all:
I am new on developing in Java3D and I have found a problem when I want to
make a zoom of the scene. Is ther any way on Java3D for doing a zoom without
moving the position of the view point?

Thank you in advance.

Rafael Pereira.



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