I'd like to create a linear pattern (one direction) at an angle.  However, I'd like the angle to be driven by other geometry.  It seems the only way to adjust the angle of direction 1, is to either type in an exact angle, or drag the direction indicator in the sketch.  Is there a way to define the angle by selecting two points in the sketch?  This way the pattern would update when the other geometry changes.  The other geometry is driven by cartesian dimensions, not angular dimensions, so the actual angle of the pattern is (a) rarely if ever an exact number (e.g. 4.237 degrees.... usually 4.237128947563298365.... degrees) and (b) the angle does not exist as a driving dimension that I could link to.

There seems to be a selection window for direction1 in the Linear Pattern property manager (default is "x-axis") but I can not seem to select anything in place of the x-axis.

I hope I've described my question clearly.  Let me know if it's not clear.  Thanks!