Explicit pipe building mode

Pipe drawing is impressive, but the default heuristic does not always do what you want. It would be nice to have a fine control option to drive the end of the pipe in an explicit shape in a stepwise manner. This would also help for belts, but pipes are most directionally flexible and tend to need fine guidance more regularly.
In pipe-driving mode, the wasd+qe would control the direction or movement of a one unit segment. The mouse could still steer but anchored to the end. The camera would temporarily center on the end of the segment. Right click would undo the last one unit.
Pipes seem to be defined as segments, so this would need to be doing some optimizing to merge the incremental units into a longer stretch.
Moving into another pipe would create a junction. Moving in an impossible direction would be rejected. Holding a key would advance in that direction.
A new mode is a complicated undertaking, but this could save a lot of build hacks and produce optimally long segments.