Building Maker is a flexible and responsive conceptual modeling and design environment linked to the Autodesk Revit building model.
Unique among software tools, it enables a cumulative understanding of the relationship between expressive and built form as the design develops. A designer can develop conceptual models independently and map them to building model components as the design progresses, working fluidly between the conceptual model and the building model. Design intent and detail are captured at the earliest stages of design.
source