Laser scanning is a relatively new technology, having been used as a precise survey instrument only since 1998.  Now, it is quickly becoming the new industry standard as a way to make very accurate measurements in complicated environments.  This is precisely why using this technology is the best solution for measuring as-built conditions inside buildings.  This instrument collects survey data points at a rate of 50,000 points per second.  It has an effective range of 400’ to 500’.  With several “scan” setups inside a room or of a building, a complete 3D model can be made of the existing conditions.  These models are then used to create 2D civil or architectural drawings, 3D computer models, and final survey documents.