[Therion] 3D models

[Wolfgang Zillig]

Hello,

I'm "playing" a little with the possibilities to create 3D models. At 
the moment I managed to get the data from a digital elevation model into 
an format which can be read and shown by therion. As output I use mainly 
the format survex (but also the vrml ouput works). An example file is 
at: http://www.student.kuleuven.ac.be/~s0167070/th/model.3d  The surface 
grid is implemented as simple lines between fixpoints.

Now my questions:

1. I want to achieve that invisible parts are hidden (the surface grid 
on the backside of the hill). Is this possible? I would estimate that 
this is not possible with the format svx but what about vrml or 3dmf?

2. The overlay of a (half transparant) jpg graphic would also be nice. 
Possible?

3. Can you reccomend a good viewer for vrml and 3dmf? I use at the 
moment the cortona vrml plugin for the internetexplorer but I'm not 
completely happy with it. I don't have a player for 3dmf at all on my 
computer.

4. Is it possible to get a 3d model of the cave by lrud data? Up to now 
I did not type these into the input files?

Many thanks for any ideas!

Wolfgang