1.3 Identifiers Within Models
The Model object and all 5 of the geometry objects that make up the Model are required to have a "identifier" key.
The "identifier" key is used to identify geometry objects in the Model and throughout all simulation engines into which the Model is translated. As such, each identifier must be unique to a given object in a model. Furthermore, because the identifier key is translated into all simulations engines, it must obey a collective set of rules imposed by these engines. These include:
- Must not contain spaces
- Must use only letters (
a-z)(A-Z), digits (0-9), underscores(_) and dashes (-) - Must not be longer than 100 characters
Since the "identifier" key is so restrictive, the Model and each geometry object also possesses an optional "display_name" key that has no restrictions imposed upon it. This can be used to match the object back to other interfaces that might rely on characters not supported by the "identifier" key.
Many of the objects that are used to extend the Model for different simulation engines also have a "identifier" key. For example, materials and constructions used in energy simulation both have "identifier" keys. When such keys are a part of an extension, they do not need to abide by the same strict rules imposed on the "identifier" key for the geometry objects. Instead, they only need to conform to the rules of the simulation engine for which they are extending. For example, EnergyPlus allows for many characters beyond those permitted for geometry objects (such as ? or &) but all characters must still be ASCII. Therefore, material and construction identifiers for energy simulation follow these rules instead of those listed above.