Building Information Models (e.g. BIM, IFC) and virtual 3D city models (e.g. CityGML) are revolutionising the way we manage information about cities. The main focus of such models is on the physical and functional characteristics of urban structures (Aien et al, 2015). On the other hand cadastral data models, (e.g. Land Administration Domain Model (LADM)), have been developed for legal information modelling and management purposes without providing correspondence to the object’s physical counterperts. However, by definition, those two aspects need to be interrelated; i.e. a tunnel, a building, a mine, etc. always have both a legal status and boundaries as well as a physical description; while it is evident that their integration would maximise their utility and flexibility to support different applications. In order to examine the correlation between those aspects, a prototype system was developed based on model driven architecture practices, empahasizing in formalization of constraints. Constraints have been proved effective in providing solutions needed to avoid errors and enable maintenance of data quality; thus the need to specify and implement them is vital. The paper explores possibilities of linking 3D legal right, restriction, responsibilities (RRR) spaces, modelled with LADM (LADM, ISO 19152), with physical reality of 3D objects (described via CityGML, IFC, InfraGML, etc). During this implementation, INTERLIS, a standard modelling language for geodata exchange, was selected as modelling language, because of its claimed good support of constraints in vendor neutral manner and ease of obtaining actual implementation. The system’s development cycle, from conceptual model to implementation of working prototype is illustrated through a proposed model for a Multipurpose Land Administation System (MLAS) for Greece. The prototype is developed in order to evaluate the strengths and limitations of the proposed conceptual model, as well as to investigate the efficiency and limitations of the existing technological (INTERLIS) tools. The process followed during the prototype development is cyclical and repetitive, providing feedback to the initial model during all the stages and improving it in terms of efficiency, reality and technical implementation. Main challenges among others during the system’s development cycle include the following: 1. how to express various LADM constraints (OCL and semiformal in standard) formally in INTERLIS, 2. how to include extensible hierarchical code lists in INTERLIS models (not natively available) and distinguish them from enumeration values, 3. how to model 3D volumetric primitives in INTERLIS (not natively available) and 4. how to link two models (legal - physical) using cross domain constraints.