What is the method of dimensioning called where all dimensions are read from the bottom of the print?

Unidirectional dimensioning is a method where all dimensions are presented in a single direction, specifically reading from the bottom of the print. This approach is designed to enhance clarity and reduce confusion when interpreting the dimensions. It ensures that the dimensions are consistently oriented, making it easier for fabricators and welders to accurately understand the measurements without needing to rotate the drawing.

In contrast, aligned dimensioning would have the dimensions oriented to be read in line with the features they refer to, which might be oriented differently depending on the view. Diametric and radial dimensioning are specialized methods used to indicate dimensions related to circles, such as diameters or radii, and are not relevant when discussing the orientation of dimensioning in relation to the drawing's base. Therefore, the focus on consistent readability in a single direction makes unidirectional dimensioning the correct answer.