Sets the value of PredefinedType attribute. This attribute represents predefined generic types for a ramp that are specified in an enumeration. There can be a property set specified for the predefined types.

• The PredefinedType is only used if no IfcRampType is assigned, providing its own IfcRampType.PredefinedType.
• IFC4 CHANGE: The attribute has been renamed from ShapeType and changed to be OPTIONAL with upward compatibility for file-based exchange.