Porosity analysis refers to the measure of “void fraction” and the characterization of the empty space. There are numerous application fields for which the analysis of pores is crucial in the understanding of the 3D structure and its mechanical properties. For example, in the field of bone research porosity is a parameter for the overall mechanical strength of the bone, while petroleum engineers are interested in the pore network connectivity to allow for transportation of liquids in oil & gas applications. Porosity analysis refers to the counting of empty space and characterization of their connections. Empty space is either fully surrounded by material on all sides, making it a closed pore, or if the empty space is not fully enclosed but at some point in 3D it can find a connection to the space outside of the object, it is defined as an open pore. The method note "MN059_PorosityAnalysis" explains why the conventional 2D analysis is very different from the 3D analysis where the values are obtained from the entire dataset. In addition, it describes in detail how to quantify the porosity in a dataset, both for open and closed porosity, and how to obtain a size distribution of the pores, as well as a list of all pores and their surface, volume, centroid location,… The method note also demonstrates how to use custom processing for noise removal functions as well as for automatic data analysis in a batch.