What does the Straight-Flow/Aisle-Flow option do in the Tugger Tab?
When generating Routes in the Tugger Tab if you select the straight flow method (on radio button in the Tugger Tab), then the software will determine distance between locations directly (i.e. straight-flow ignoring aisles). In an assembly line situation this is a problem because the software will assume that you can go from the left side of the line directly to the right (i.e. over the conveyor).
If you use the (aisle-flow) method to generate Tugger Routes, then the distance from the left to right sides of an assembly line would be determined by using the aisle down to the end, across and back again. Therefore, the module is far more likely to visit all of the locations on one side of the assembly line, turn around at the end, and visit the other side in the sequence of travel. Obviously, it will also visit locations along the left side of one line and right side of the adjacent line which share the same aisle - sequenced from one end of the assembly line to the other.
Additionally, it is common that your aisle network may not have all of the join lines created when running your first Tugger Flow Study. As such, I typically run the Tugger module first as Straight-Line to get my points specified and double check my locations.
Then, I Join-Locs to my aisle network and rerun the Tugger module using the Straight-Flow method to get the Tugger route sequences correct.