This part of ISO 15530 specifies requirements (for the manufacturer and the user) for the application of (simulation-based) uncertainty evaluating software (UES) to measurements made with CMMs, and gives informative descriptions of simulation techniques used for evaluating task-specific measurement uncertainty. Furthermore, it describes testing methods for such simulation software, along with advantages and disadvantages of various testing methods. Finally, it describes various testing procedures for the evaluation of task specific uncertainty determination by simulation for specific measurement tasks carried out on CMMs, taking into account the measuring device, the environment, the measurement strategy and the object. This document describes the general procedures without restricting the possibilities of the technical realization. Guidelines for verification and evaluation of the simulation package are included. The document is not aimed at defining new parameters for the general evaluation of the accuracy of CMM measurements.