[GRASS-user] NVIZ grass6.1 cvs, crash

[Glynn Clements]

Robert Kringel wrote:

> We are currently running grass6.1 CVS-Version (20/05/2006) compiled
> for a Pentium IV running under Suse Linux 10.1. The Computer has a
> i845 Intel-onboard graphics chips. The Xserver uses the module i810.
> Everything seemed fine.
> 
> we are working mainly with the r3.modules to visualize contamination
> clouds interpolated with v.vol.rst. Trying to visualize volume-maps
> crashes NVIZ in three ways.
> 
> 1. calling NVIZ from gis.m produces 2 Windows, which soon dissappear
> without further message
> 
> 2. calling NVIZ from the grass prompt with "NVIZ &" and adding a 3d-map
> immediately crashes NVIZ
> 
> 3. calling NVIZ from the grass prompt with "NVIZ &" without data, loads
> the NVIZ program. NVIZ also loads the 3dmap, trying to set an isosurface
> seems to work, but visualization fails. The program does also not show
> the usual frame.
> 
> A hint would be highly appreciated:
> 
> -- Is 3d acceleration mandatory for work with NVIZ ?

No. OpenGL is mandatory, but it doesn't have to be accelerated.
Whether the performance difference matters depends upon the resolution
of the data.

> -- could this be a missing graphics-library?

No. If you don't have the OpenGL libraries, NVIZ won't even run.

> -- Are there any known problems with NVIZ (separate setup,
>  do I have to recompile)
> -- How can I stop this behavior?

NVIZ problems are usually due to either a bug in the DRI/DRM drivers,
a bug in a vendor-supplied OpenGL library, or
installation/configuration problems (e.g. using the standard X.org
OpenGL library with a DRI driver which requires the vendor's library).

It may help to type:

	export LIBGL_ALWAYS_INDIRECT=1

before running NVIZ. This will disable the use of DRI/DRM (hardware 3D
acceleration) and use the X server's software 3D renderer. 
Alternatively, you could try using Mesa (a client-side software OpenGL
implementation).

-- 
Glynn Clements <glynn at gclements.plus.com>