I set the model tree to show only components and then expand all . Then save the tree. The result is space-character indented text file and can be parsed pretty easily for structure. Groups and patterns make for a small twist, but accounting for those is easy enough once the realization they need treatment is clear.
Basically, every time the indent increases, unless a group or pattern, the level increases and all those parts are in that assembly. If the level decreases then that's the end of an assembly, If it's a group or pattern, then if the level decreases by one or more, that's the end of the group or pattern. Keep the current assembly on a stack and pop the correct number off whenever the indent decreases.
