These steps must be followed for the configuration:
- Identify all the objects in your scene that do not change position, size, and material. Possible candidates are buildings, walls, terrain, props, trees, and others. In our case, it will be all of the objects aside from the FPSController and its children.
- Select these objects and check the Static box from the Inspector tab, as shown in the following screenshot. If any of the selected objects have children, Unity will ask if you want them to be considered static as well. If they meet the requirements (fixed position, size, and material), select Yes, change children in the pop-up box: