better 3D surfaces ?

["Richard Tyc" <richt(at)sbrc.umanitoba.ca>]

I have been trying different methods for visualizing our  MRI data in 3D and
I prefer 3D volume rendering although it is very CPU intensive.  I have been
looking for a better shaded surface approximation of the data (2D slice data
, typically 256x256 and 5-25 slices).

I have been trying  the SHADE_VOLUME procedure
eg.

oHeadSurf = OBJ_NEW('IDLgrPolygon', color=[100,100,100], reject=1, $
                        STYLE=2, SHADING=1)
Shade_Volume, 3Ddata, 1, vertices, polygons, low=1
oHeadSurf->SetProperty, data=vertices, polygons=polygons

But I notice my volumes always look like extruded slices from each data set,
so in the z (or slice) direction, it is very "step like" with no
interpolation in this direction.

Is there a better way of showing 3D data created from individual slices
where the slice resolution is usually much less than the image resolution.

Thanks
Richard Tyc
SBH Research Center