I have questioned myself the logic when it comes to divide path in conceptual massing environment in the past. Recently I am working on an adaptive component for a panel where it requires a louver as part of the panel. I start with a 2 point adaptive family as a louver blade and nest it to the next family. The next family makes out of a set of reference lines and a frame, I have two edges that I use "Divide" to set up my "array".
I then place the blade family and try to use "Repeat" and lay out a series of blade.
It turns out the blade is going wild! At first I thought I have snapped my AC to the wrong node so it behaved unexpectedly.
After some trial and errors, I learn there is something I didn't realize before. For some reasons, when choosing an edge to divide path, one side of the edge has the node sequence backward; thus it results to an unpredictable array.
There is a hidden setting under the path properties. Select the path, check the "Show Node Numbers" and I am able to see the numbers on the path. Obviously they are going different direction.
The fix is quite easy. Check the box "Flip Direction" under the properties, it will set the path to the correct direction.
Try it again with Repeat and this time it works like a charm.