If you don’t get the title of the tip, that’s OK.  It’s easier just to say that it’s hard to explain if you don’t already understand, but at the same time it’s not necessarily a bad thing if you don’t.  Either way, I’m guessing that there’s a little tip that you didn’t know.  The one that tells you which side of a reference plane that extrusion is going to actually extrude from.  Ever heard of it?  No!?  Well here goes.  This is, in my humble opinion, another short but AWESOME little tip!

The +’s and -‘s of Reference Planes:

If you create an extrusion (for instance) on this reference plane that you just created, you know now which way the extrusion is going to go if you assign an extrusion start of 0 and end of 5′ (for example).  Any positive part of the extrusion will be ABOVE this reference plane and any negative part of the extrusion will be BELOW the reference plane.  Now you don’t have to guess which way the Extrusion is going to go and you can make sure that you don’t have to use negative calculations in your formulas to control certain extrusions now.  So from now on, you’ll be paying a bit more attention to how you draw your reference planes, eh!? The series of reference planes below were drawn in a clock-wise order and direction.

So there you have it; short, sweet and yet another incredibly powerful arsenal to your bag of tools.  Hope you enjoyed and hope to see you again for another, Revit TotD!

-Carl