Building Information Modeling (BIM) was conceived as a working method for networked planning using software assistance. Multiple stakeholders in the construction industry are involved in the design and management of digital representations of the physical and functional characteristics of a facility in the BIM model. Design variant management coupled with documentation and recording of design knowledge are the main goals of this paper. The use of a BIM-based plugin for design rationale documentation grantees support for other architects in the early design phases, to retrieve suitable building designs and ideas, based on their needs and architectural concepts. Uniting Design Episodes with different Variant Types allows the architects to receive inspiration and freely select important parameters for their design of the building in advance. These input parameters are compared with other BIM-based design graphs, following the graph representation approach. The relevant design options and variants corresponding to the new project are visualised and stored for both current and future users. This can lead to cost and time savings and allow the possibility for future extensibility in terms of other analysis parameters (such as the level of detail or energy efficiency).