The paper describes the use of immersive technologies and Digital Twins in the architecture, engineering, and construction (AEC) industry. Immersive technologies have immense potential to improve interdisciplinary collaboration as they utilize a visual representation of virtual objects in their real-world perspective. This immersion facilitates effective communication between all parties involved, e.g. to identify errors during the planning and construction of buildings. A specific example of such interdisciplinary collaboration is kitchen planning. The architect draws the house and room plans, the kitchen planner plans the kitchen according to the homeowner’s wishes and the craftsmen then carry out their installations according to the plans for electricity, water, and heating. All plans are based on flat floors and perpendicular walls. However, this is rarely the case in a real building. The challenge with the exact visual representation of virtual objects in the real world using AR therefore lies in the positioning of objects such as a cupboard in relation to the non-orthogonal coordinate systems that result for each room from the real floors and walls. The paper presents an assistance system that integrates immersive technologies and Digital Twins. It is a solution approach for the transformation of object properties based on orthogonal coordinate systems into the non-orthogonal coordinate systems prevalent in reality. With the assistance system, the kitchen planner can create his plans using virtual reality (VR), customers can experience their kitchen virtually and the craftsmen can then be guided using augmented reality (AR), e.g. by precisely localising drilling positions for cabinets.