Final answer:
The sill height of a window is an instance parameter which is true. This attribute can vary for each window throughout a project to meet specific design requirements or building codes, distinguishing it from type parameters that would apply to all windows of a certain type.
Step-by-step explanation:
The statement that the sill height of a window is usually an instance parameter is true. In the context of building design and construction, particularly when using Building Information Modeling (BIM) software, instance parameters refer to attributes of an object that can be modified for each instance of that object within a project. For instance, while the type of window (i.e., its material, thermal properties, overall dimensions, etc.) might be defined by a type parameter that remains consistent across all instances of that type, the sill height can vary depending on the specific requirements of each location where the window is placed.
For example, a window's sill height could be adjusted according to the design requirements, potentially for aesthetics or to meet specific building codes related to the egress, light, or ventilation. Because these requirements can change from one window to another, even within the same building, the sill height would indeed be set as an instance parameter rather than a type parameter which would apply universally to all instances of that window type in the project.