3d texture mapping artifacts

3d texture mapping artifacts

Post by Angus Dorbi » Wed, 10 Sep 1997 04:00:00

> Please help...

> Want to allow a user to interactively position/orient a volume rendering
> of the brain and hand-trace along sulci (cavities) of interest.

> Currently using 'volren' (SGI volumetric rendering code using texture
> mapping) to volume render a brain.

> Problem:
> I want to see the curvature of the brain's surface (cortex), yet when I
> set opacity high for the cortex, artifacts appear.  These artifacts seem
> to occur where a portion of the brain's surface is nearly parallel to the
> view plane.  Since the cortex is highly convoluted, nearly every portion
> of the brain displays some facet nearly parallel to the view plane and
> artifacts abound.

> Visually, these artifacts look like rings on a topographic map and if
> correct and stationary, they might actually guide a user's hand while
> tracing.  However, because they shift and warp with varied viewing
> location, the reliability of each tracing becomes dependent on camera
> position and integrity is suspect.

Sounds like you need to draw more slices to sample the volume set.