There two ways to anchor virtual 3D content in real-world environment. In the Plane Mode, you'll firstly move around camera to detect a plane area, such as floor, table, etc. Then you can tap to place a BIM model on a plane found. This is used for environments in which you can physically move around. When it is hard to find a plane in surrounding environment, you can consider using the Floating Mode that simply places a BIM model in front of your camera. Spatial tracking might be lost if you move too far away from the initial position.