[GRASSLIST:5256] draping vectors in NVIZ

[Nick Cahill]

I am draping circles produced by v.circle and other GRASS programs over 
a DEM in NVIZ, and getting odd results. Depending on the resolution of 
the region when I start NVIZ, and the polygon size within NVIZ, I get 
spike-like vectors projecting from the circles, either up and down, 
north-south or east-west. At  higher resolutions I get more spikes, and 
with smaller circles I seem to get longer spikes. It's not predictable, 
however -- not all circles get spiked, it seems. Has anyone seen this 
behavior, and is there a way around it? I'm running GRASS 5.0.0 on Mac 
OSX 10.2.3.

Many thanks,

Nick Cahill
Dept. of Art History
Univ. of Wisconsin-Madison