The Model Structure Report (MSR) provides a Bill-of-Materials (BOM) view of a CAD document structure that excludes those models that do not serve a functional purpose in the CAD design. It is not to be confused with the BOM that results from a Windchill Product Structure.

Unlike the relationships noted in the previous section, inclusion in the Model Structure Report BOM is not purely an attribute of the model structure; it is an attribute of the CAD document for the model and of its existence in an assembly (for example, the presence of a member link). An object that is not an MSR BOM item in one model structure should not be an MSR BOM item in any model structure in which it occurs. As such, the Bill-of-Material contribution of a model will be an attribute of the CAD document that contains the model file. The requirements for BOM membership are described in more detail in the sections that follow.