Let's say I have a set of drawings from an architect (.dwg) and I would like to overlay keypad, TV, touchpanel data on top of the elevation views they have created. In theory, I should be able to create shapes that are dimensionally accurate to actual devices and be able to simply drag the drawings from my own database onto the architects plans on a new layer, correct?

how do I create these "symbols' such that their attributes are accurate to real world and that the dimensions will perfectly match those of the architects plans? How do I answer the question when opening a .dwg regarding the X units = 1 inch?

I need to understand the procedure for creating a database of accurate elevations of devices and being able to insert them onto architects elevations rapidly and accurately.

Also, how do you draw measurement lines to show distances to and dimensions of shapes?

Thanks!