Ordinate dimensioning

[Spursman]

My question is about positive and negative dimensioning in ordinate dimensioning. Say I have a panel to a chassis. There is a cutout from the front and a spotface from the rear. If I dimension the hole from the front (front view) from left to right, that is a positive number. Then I give a rear view. When I dimension from the same corner (formerly on the left and now on the right side of the view) does that number now become a negative number? I understand negative and positive from the xy graph, but if the part is flipped over in the view, does that now become a negative number? My feeling is that it would still be a positive number, but I may be wrong.

Tim

 

[3DDave]

Negative dimensions only make sense in tables that are related to coordinate systems. Otherwise they have no directionality and represent the distance between items, which can only be greater than or equal to zero.

 

[Tunalover]

Agreed. Dimensions to either side of an origin are always positive but it must always be clear what side of the origin their on.

Tunalover
Electro-Mechanical Product Development
UMD 1984
UCF 1993