How to scale using a known dimension

[nscherneck]

I was sent a site plan that was not drawn in full scale (for whatever reason). I remember learning a way to scale all objects in model space using a known dimension. I only recall setting a point at each end, using the scale command, then NODE, but i cant remember the rest. Does anyone recall how to do this?

[lpseifert]

Try using the Reference option of the Scale command

[nscherneck]

Oh thats what it was. Thank you.