AutoCAD Dimension Help

[JoshIsaacson]

I've been trying to figure out these CMM measurements on concentricity by making a model in AutoCAD in 3D space. The problem is in AutoCAD when I take a linear or ordinate dimension of a line in 3D space from point (2.4078,2.8863,18.6762) to (2.5097,2.9879,18.6775) CAD give me a distance of about .0923 inches. Throwing these points into the distance equation Sqrt((2.4078-2.5097)^2+(2.8863-2.9879)^2+(18.6762-18.6775)^2) I get a value of .143902. I figured it was some sort of scale problem so I looked in the dimesion style menu and under primary units I have a Scale Factor of 1.000 and under DIMLFAC it is also set to 1.000. So I have no idea where AutoCAD is getting this number from. Please help

Thanks
Josh

 

[Occupant]

I don't know what you did wrong, but you did. Autocad gives me the exact same dimension as your calculation. May be you have Object Snap set wrong.

 

[borgunit]

I draw a line between these two points and it comes exactly .143902 long.

http://mechcad-insider.blogspot.com/

"The fear of the Lord is the beginning of wisdom"

 

[IFRs]

I think the dimension reports the distance in the current UCS, not 3D distance.