Digital Elevation Models + Aven

[Imperial College Caving Club]

Hello all,

We [ICCC] recently got some DEM data [Digital Elevation Model] data
(provided by the Slovenian Academy of Sciences and Arts) for the
Mountain Plateau to which we have our yearly expedition.

After a fair few hours of effort [most of which were spent crashing
Aven + X-Server as the excitingly documented .3d file format was
wrestled with ;)], we've managed to incorporate the data into the .3d
model of our surveys. The current data is +-10m, with horizontal x/y
grid of 25m. Currently its implemented as lines of lattitude +
longitude varying in height, but one could easily interpolate the data
to create contours + feed them into Aven if so wanted.

Probably easier to show rather than say;
http://sbl.ath.cx/jarvist/mig_dem/hollow_mountain2.jpg

much more pretty .3d model available here: [1.4mb; requires 1.1
version of survex/aven]
http://sbl.ath.cx/jarvist/mig_dem/hollow_mountain2.3d

Messy Code + horrific .sh script used to cludge two .3d files together are here:
http://sbl.ath.cx/jarvist/mig_dem/
To say they are a little rough around the edges is a slight understatement :)

Its been taken about as far as possible without having to open up the
Aven sourcecode and make some changes;

'Surface' legs are a good order of magnitude slower to render [due to
the way the dotted-lineness of them is implemented?], and the colour
depth-profile is rather useful to see where abouts our mythical 'walk
in entrance at -700m' is going to appear, so I may look into creating
a seperate 'flag' in the .3d files for 'DEM data' and see whether it
can be rendered as something pretty + semi-translucent with GL.
Once my exams are over that is! 

Jarvist

-- 
Imperial College Caving Club
http://union.ic.ac.uk/rcc/caving
ic.caving [AT] gmail.com