Hi, I am currently learning how to use Therion to draw up a detailed survey. My survey is split into several "caves", each of which has its own .th and .th2 file. In the .th file for each cave is a separate "map", so that the cave can be rendered separately. cave1.th: survey cave1 input "cave1 plan.th2" input "cave1 ee.th2" map cave1MP scrap1 scrap2 endmap centreline ... endcentreline endsurvey cave2.th: survey cave2 input "cave2 plan.th2" input "cave2 ee.th2" map cave2MP scrapa scrapb endmap centreline ... endcentreline endsurvey Then I have an overall file which combines the maps called allcaves.th: survey allcaves map allcavesMP cave1MP@cave1 cave2MP@cave2 join ____________ endmap centreline ... endcentreline endsurvey Imagine the two caves join in scrap1 (id "foo":0) and scrapb (id "bar":end), and I want to use a join command to make the scraps join neatly (I have already positioned the passage ends very close to each other). Could you please tell me the syntax needed to make the join command reference the correct points of the correct lines inside the correct scraps inside the correct maps? Every example of the "join" command I could find assumes you were trying to join scraps inside the same map, and did not show how to reference items in a sub-map. As a result, I have not been able to work out how to construct a valid join command for this situation. Many thanks for any information you can provide. Tarquin