When inspecting a PCB earlier today it occurred to me that all traces you find on modern PCB's are confined to 45 degree increments with respect to the (typically square) board edges.
What is the rationale for this? Is this a fabrication consideration or something electrically inspired?
It's usually a default snap to that angle in the EDA software we use to lay out boards. It can usually be overridden, but there is seldom a good reason to do so- 45 degree angles do the trick and keep things neat. It's also easier to keep the spacings within rules when endpoints snap to a certain grid when you only have to deal with the grid itself (parallel traces that are vertical or horizontal) and spacing on 45 degree angles of 0.7 times the grid (parallel traces that are at 45 degree angle relative to the X or Y axis).
