Hi,
I am currently working with some old Autocad drawings. When I open them up in eDrawings, and try to take measurements using the measure tool, it always claims that there is a z-component to the dimension (ie. dX=27.644 in, dY=3.362in, dZ=275.59in, Dist=276.993in). This means that I have to get out my calculator (x^2 + y^2)^.5 to get the acutal planar distance (27.848in). How can this happen on a 2D drawing?
The worst part is when the z component isn't very large, and the Distance number seems reasonable so you use it, not realizing it is incorrect.
Dean,there really could be an elevation difference between the start and end points of a line in AutoCAD. AutoCAD uses a 3D coordinate system, supports 3D entities and 3D views, so you might be getting an actual distance. If this is the case use the dimensioning tool under mark-ups instead of measure since it displays the dimensions projected flat to the screen