Offset-Based Marker Placement for BIM Alignment in Mixed Reality

Mixed reality (MR) visualization, which involves displaying virtual content mixed with a view of the real-world, has recently been explored for the inspection of building work. This process requires aligning a building information model (BIM) with physical construction sites. However, achieving accurate alignment poses challenges in MR applications. Marker-based methods, although more reliable, have limitations in complex environments where pre-installed markers are inaccessible in certain locations and their installation and maintenance are costly and labor-intensive. This paper introduces a new offset-based marker placement method to align BIM models in MR. This approach involves placing markers offset from the corners determined by the geometric features of the building. The markers are placed during the registration process, without the need for a pre-installation stage. The effectiveness of the method is demonstrated on a site with pipes of different sizes, showing that the offset-based markers provide accurate BIM alignment, comparable to conventional marker-based methods.