Re: Volume visualization strangeness


Looks like you're saying this is a feature. My concerns with resampling
the grid to make things cubic are that I'm going to pay a large memory
penalty (maore than an order of magnitude greater in the case of the
61x61x5 example) and I risk aliasing the original grid. In addition,
users of ncBrowse will be stuck with how I choose to resample the grid. 

----- Original Message -----
From: Bill Hibbard <billh@xxxxxxxxxxxxx>
Date: Thursday, February 13, 2003 3:41 pm
Subject: Re: Volume visualization strangeness

> Hi John,
> > You are right--changing the aspect ratio didn't fix the 
> problem.. So is
> > the rendering problem with non-cubic grids a VisAD bug or VisAD 
> feature?
> VisAD implements volume rendering as sets of planes perpendicular
> to the X, Y and Z axes. The choice of axis changes as the box
> rotates, to the axis closest to parallel with the view direction.
> This techniques is widely used (and first described in my paper
> to the 1989 volume visualization workshop), but does produce weird
> images when volumes are very non-square like your 61 x 61 x 5. Try
> Curtis's suggestion of resampling to 61 x 61 x 61.
> Cheers,
> Bill