length tool

[diesellam]

When I use the length tool in dwf file, how can I make it a linear dimension instead of a true length dimension?

For example, when I look at the model in section view. I want to measure the distance from the face of the soffit to the face of the wall.

Also the point location tool, is there a way I can adjust the coordinate so that it'll show the true (X,Y,Z) location? Like the lower left hand corner of the building is (0,0,0)?

Is there a difference between file format .dwf vs. .dwfx?

Thanks in advance.