Hi, I'm currently fighting with extended elevations in Therion. Before I start posting a whole lot of stupid questions, I'll start with clarifying what the right way to do this is. The cave isn't huge (3.5 km), but is relatively complex with multiple interconnected loops. The data is in survex format (ftp://ftp.gns.cri.nz/incoming/JennyB/therion/107.3d). When I've draw plans in therion, I've successfully used survex's 3d file. I'd like to do the same for my extended elevation. I'm not sure which of the following is the correct way to go (I run into problems each way!): 1. read in the original .3d file for the cave (the same one I use to draw the plan), and then choose where to break loops (and extend legs to the right or left) in my .th file as documented http://therion.speleo.sk/samples.doc/25.html. For example: import ../../../all.3d -surveys use survey 107 centerline extend ignore oldrift.17 oldroute2.17 extend left ent.13 extend right ent.16 endcenterline input 107ee_ropeless.th2 endsurvey 2. use survex's extend command (http://survex.com/docs/manual/extend.htm) to create an extended 3d file, but control the extend right/left in the .th file as above. I guess I'll need to control breaking of loops in survex via the .spec file, otherwise survex will choose where to break the loops for me. This is roughly what the mailing list suggests is the correct answer (though I note breaking of loops is not mentioned): http://mailman.speleo.sk/pipermail/therion/2007-November/001685.html and is the approach I took with mixed success a couple of years ago. I did manage to generate an elevation without needing to break any loops (either with "extend ignore" in therion or "*break" in survex): http://expo.survex.com/expofiles/surveys/107/107-elv-2013.pdf but we've since then found more cave and closed more loops, and it doesn't work on the new data set, which is what started me fighting and made me wonder if I was doing this the right way. 3. use survex's extend command with the .spec file to create a 3d file to control the breaking of loops and which direction to extend (left or right). Don't do any "extend ignore" or "extend right" in the .th2 file. Who has successfully drawn extended elevations using survex data? Which approach did you take? Are there any clever tricks, or things I might be missing? Thanks, Jenny