The invention relates to a method and a device for generating a virtual installation model (2) as an image of a real installation (1). As a database therefor, digital picture data (4) representing pictures of a real installation (1) on the one hand and installation components (13) of a component library (6) on the other hand are used. The data of the installation components as well as the digital picture data (4) of the real installation (1) is evaluated by means of an image analysis (5). Based on this analysis, the identified installation components (13) are assigned to the virtually generated installation model (2). The virtual image of the real installation thus created serves to document the actual structure of the installation/facility, to simplify failure analysis, e.g., in areas that are difficult to access, and/or to operate and monitor the installation/facility. In addition to geometric data, functional data, etc. of the installation components are also stored.