Re: changing the default zoom properties

• To: Vladimir Altuna <Vladimir.Altuna-Renexter@xxxxxxxxxxx>
• Subject: Re: changing the default zoom properties
• From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Date: Fri, 24 Nov 2000 09:06:09 -0600

Hi Vladimir,

> Does somebody know a easy way to change the default zoom properties in
> order to keep the axes
> on screen when zooming?

I'm not completely sure what you are refering to, but suspect
it is graphics that disappear beyond the fore and aft clipping
planes when you zoom in with SHIFT/left mouse button.  This is
hard to do much about.  The fore and aft clipping planes
define the dynamic range for Java3D's Z-buffer values, and
moving them way out results in image artifacts due to lack of
Z-buffer resolution.  Also, when you zoom in some graphics may
end up behind the viewer's eye which is tough to correct in
any case.

One approach is to provide your own zoom control that adjusts
the ProjectionControl matrix to combine translation with zoom
to keep objects in your scene from getting to close to (or
behind) the viewer.  You can experiment with this in VisAD by
manually translating in X or Y (CTRL/left mouse button), then
rotating that translation back into the Z away from you, then
zooming.

You might be able to get some wisdom on this subject from
java3d-interest@xxxxxxxxxxxx.

Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html

• References:
  • changing the default zoom properties
    • From: Vladimir Altuna