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