A Universal Measuring Machine (UMM) is a measuring device for objects where geometric relationships are the most critical element, where dimensions are specified by geometric positions (see GD&T) rather than absolute coordinates. [1] The original use of these machines was to inspect gages and parts

In addition to the four geometric errors of positioning error, straightness error, angular motion error, and perpendicularity error, the CMM​ also has four geometric errors due to force deformation, thermal deformation, measurement system, probe system, control system, data recording and processing.