Hmm Something is happening to the lox model wall a little remote from the wall you are changing. Intriguing. I added -layout-colour map-fg [97 86 38] to the export of the pdf, to check what therion interpreted as inside and outside. All seems OK. I cannot see any problem with -reverse or -outline settings, but I did not check exhaustively. I cannot imagine that superposed ceiling step lines would make any difference (They are not rendered in loch so I presume they are ignored). Only style thing that you do different to I is that you seem to start a new line each time you change the subtype, where as I tend to use long lines and change the subtype from invisible to bedrock or clay or whatever at internal points. This makes it less likely that you 'lose' underlying lines. Should make no difference to the characteristic we are discussing. As far as I can see the file with all wall:invisible should be good, but it is not. I have perhaps similar issues with many of my scraps rendering in loch, and I have just put it down to bugs that will be fixed in due course. I'm done. Someone else? Bruce -----Original Message----- From: therion-bounces@speleo.sk [mailto:therion-bounces@speleo.sk] On Behalf Of Footleg Sent: Thursday, 10 May 2012 8:12 a.m. To: List for Therion users Subject: Re: [Therion] Wall visibility affecting lox model There are other wall:invisible lines in my scrap. It is only when I switch one of them to wall:invisible from visibility off that my lox model walls are all rendered OK. The others are still wall:invisible but these also have identical lines of type ceiling step running along the same path. Maybe that makes a difference? I've attached a mini project with the two versions of my ths file. One gives a good lox model, and one does not. Footleg