[Therion] Entering survey sketch without walls

Bill I've been misleading you (and everyone). I should not multi-task quite so much. I will try to rectify the situation tomorrow with a sketch. In the meantime... line wall -subtype invisible is what should be used for the open ends of scraps in your example, and should allow semiautomatic joins. line wall -visibility off will preclude the possibility of semiautomatic joins, but does have a use case in large open voids that need to have a scrap join where there are no (real) walls at all. Manual point joins will be required across those boundaries. A sketch tomorrow… Bruce