http://grockit.com/blog/collegeprep/files/2010/08/2.jpg
Ok so pretend there is something like a ceiling light at Y in the picture
and another ceiling light on a different elevation (for example a dropped ceiling in an adjacent room) at point X in the picture.
To measure the center-to-center...
I've always been confused by this concept:
How do you measure center-to-center in engineering terms when the objects are on different x and y coords?
When objects cross the same x or y plane it's simple enough, just draw a straight line from center to center. When they aren't on the same x or y...