hi there

you could use a CPlane(View -> Cplane). Just execute the command and set a new origin by using the Orientation picker

http://moi3d.com/2.0/docs/moi_command_reference5.htm#cplane
http://moi3d.com/2.0/docs/moi_command_reference11.htm#orientationpicker

"Setting a global CPlane will also affect x,y,z coordinate point entry, with the coordinates evaluated in the CPlane's coordinate system instead of in world coordinates. For example typing in 0,0,0 will place a point at the CPlane's origin instead of the world origin. You can prefix typed in points with a w (for example w5,2,1) to enter in a world coordinate point instead when a CPlane is active. The x,y,z point coordinate readout in the bottom toolbar will also show the location of the mouse in CPlane coordinates instead, with a "c" being displayed in front of them to indicate they are CPlane coordinates and not world coordinates."

cheers,
marco