Strong versus Soft Typing

BIM applications support strong, soft, or a combination of strong and soft typing as follows:

Strong	Requires the creation of a new type if any property is changed. This is applicable during the construction documentation and product specification phase.
Soft	Does not necessarily require the creation of a new type if a property is changed. The user must decide which property changes require a new type. This is applicable during the conceptual design and design development phase.

Note: The IFC specification does not define whether a change of property requires a change of type, or which properties must be shared by all instances.

Note: Although not defined in the FM Handover Model View Definition specification, COBie has a preference for strong typing.