PTC Integrity Modeler is a standards-based, graphical, systems and software engineering tool which,caters well for large distributed teams working on mission-critical and safety-critical projects involving the integration of software, hardware and human process. It uses UML and SysML modelling, among other notations. It is very much intended for a Systems Engineering “systems of systems” culture, where some of the systems may be implemented as mechanical or electronic systems. It is thus part of a larger suite of integrated, repository-based, systems engineering tools. It has a Product Line Engineering capability and supports Variability Modeling (using ISO 26550 compliant Orthogonal Variability Modeling (OVM), which is an important differentiator from similar products.