[GRASS-user] 3D graphics, two problems

[Tomas Lanczos]

I have two questions regarding 3D rasters:

1. is there any rule of thumb for generating 3D rasters by v.vol.rst? 
The 3D raster represented by a cross section on the picture (see the 
attachment) is generated from 2D vectors layered each 250 m in interval 
-500 to -6000 below sea level. in the central part ther is apparent a 
strong oscillation, the outer part is segmentated. How can I avoid those 
artifacts changing settings (npmin > 500 is causing segfaults) ?

2. Using nviz the 3D raster is allways visualised above 0 m a.s.l, 
however all is below see level (as I explained above). The raster 
surface is visualised correctly, it should penetrate the 3D raster. Am I 
doing something wrong, or is it a bug?

Many thnx in advance and regards

Tomas