Have just had some partial success at adding a surface to my outputs. I have cave data, georeferenced to the same co-ordinate system as that below, that covers at present 1km x 1km in plan, but I expect to add other systems to extend this area. I have cropped a jpg topo map image to an area 3km x 3km I am exporting at 1:1000 to pdf (900mmx1012mm) I have labelled grids at 100m centres on the cave map, so I know from observing the output that the grids and the cave are correctly georeferenced. Trouble is the jpg seems to be "zoomed in" many times too much. My *.th data as follows; survey. surface #Canaan Road South Topo cs EPSG:27200 #NZ Map Grid 1949 bitmap ./Surface/Canaan_South_Topo_NZMG_990210_020240.jpg \ [0 0 2499000 6021000 100 100 2502000 6024000] grid-units meter # grid <origin x> <origin y> <x spacing> <y spacing> <x count> <y count> # grid-flip (none)/vertical/horizontal # [grid data] endsurface . endsurvey I have tried reducing the co-ords to the NE corner of the image, and seem to get a more legible, bur still erroneous, surface image. Makes me suspect I'm exceeding some software limits and there's an unreported error, or that I'm just making a dumb mistake. A possibly related matter, I have had "sketches on" (no quote marks) in my layout since my first (almost) Therion steps last year, and not once have I had my jpg sketches exported to pdf. I expect they should, and I recall that the samples provided seem to do so - I could find no difference between my code and the samples. Any ideas on these two issues? (surfaces most importantly) Also the above code does not produce a 3D lox model. Is that because a surface is either 2D or 3D but not both? It would be nice to have at least a 2D image above my lox model until I can get a grillage of elevations sorted. Regards Bruce