||Process models have several fields of application. THe research community of construction IT has used process modelling methodologies for several years to analyse and share information. The construction industry has applied process modelling, among other things to better understand current business, to improve or innovate business and to create information systems that support business. Developing a business by using process models needs usable process models. This licentiate thesis describes how process mdels presented in a computer environment can be made usable to practitioners of the construction industry.A structure of concepts is developed that describes interactive environments for process models. The concepts are of two different types: objects and actions. Objects are components that carry the information, and they are not examined in this research. Twelve different actions are identified in the thesis: overview, zoom, filter, details-on-demand, decompose, relate, history, extract, browse, search, compare and find. Based on the concepts developed a prototype is developed. An authentic model built according to the IDEF0 process modelling method is displayed in the prototype. Finally, a usability study is performed to gain knowledge about the concepts and their implementation in the prototype.