Robert Grzeszczuk (rg@hoek.engr.sgi.com)
Fri, 18 Jun 1999 09:04:58 -0700 (PDT)
You hit a glitch within voGeometryActions::polygonizeMPR(). Just as you
describe, when slicing through a stack of 2D images with a plane that is
parallel (or very nearly parallel) to one of the major axis, the
interpolation
weights are not computed correctly. Fortunately, it was a quick fix, so it
should make it into the patch we have been working on. The patch fixes
several
functional and performance related problems and is now code complete. We
still
need to thoroughly test it for regressions, package it, and release it, but
that shouldn't take long. We will keep you posted.
Sorry for the inconvenience.
-rg
On Jun 15, 2:25pm, Mark Davey wrote:
> Subject: MPR question
> Hi,
>
> I have taken the first Multi Planar Reformatting demo that comes with
> Volumizer (using voglMPR1.cxx) and tried to adapt it so that the user
> can view different slices by changing the value of 'pos' in the line
>
>
> planeEquation = aSamplingPlaneSet->generateEquation(pos);
>
> where pos ranges from 0.0 to 1.0. This seems to work find when the
> command line says to use 3D interpolation (i.e -3D) but when -2D is used
> there seems to be a problem. If the volume is aligned with the viewing
> port then as 'pos' is slowly varied it is seen that there is not actual
> interpolation between slices only a darkening of the current slice until
> at a discrete point the next slice is displayed.
>
> I have to say that this only happens when the dataset is aligned with
> the viewport.
>
> Can anyone help me to understand what is going on here.
> Im using an Onyx2 which does have 3D texture memory, so I could get
> around this problem, but I want to make my code as machine independent
> as I can..
>
> Regards,
> Mark..
>
>
> --
> From: Mark Davey
> Dept. of Medical Physics, UCL.
>
> TEL: +44 (0)171 915 1673.
> FAX: +44 (0)171 837 9279.
>
> Institute of Laryngology and Otology,
> 330 Gray's Inn Road,
> London.
> WC1X 8GE.
>-- End of excerpt from Mark Davey
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