I have two proposals to upgrade the “Draft angle analysis” tool to make it even more versatile:
Add an option called “History enabled curve” to pick a straight line and automatically adjust the draft angle based on the modifications of the former. This option should be history enabled to work this way. Note that this is not supposed to be a replacement for the existing option called “Curve or edge”, because the latter is also useful due to its lack of history. The automatic one that I propose here is for situations where the user needs to test the draft angle multiple times and needs the graph to quickly follow the changes of the directional vector without the need to press the “Set…” button again after each change.
Add an option called “Normal to surface” to pick a surface and use its normal direction for the direction of the “Draft angle analysis”.