# Named Ranges

Creating a named range provides an easy-access method for subsequent use of a range. Named range creation is performed using the model range command. For instance:

model range create 'fred' position-x 5 500 id 100 200 group 'external' not


Once created, the named range is applied on subsequent commands using the named-range keyword in a range phrase:

geometry group edge 'mainedges' range named-range 'fred'


This is equivalent to:

geometry group edge 'mainedges' range position-x 5 500 ...
id 100 200 group 'external' not


Since the group defined and named 'mainedges' in the second command uses 'fred' for its definition, it might seem that the two refer to the same thing. However:

zone cmodel assign 'mohr' range named-range 'fred'   ; will work
zone cmodel assign 'elastic' range group 'mainedges' ; will fail


The latter command fails because 'mainedges' is a group of geometry faces, so invoking it for a command that affects zones is nonsensical (error). If the group 'mainedges' comprised zones, then the usage would be acceptable. See below for further discussion.

Named Ranges vs. Groups

The group and the named range have similarities: either provide a convenient mechanism for naming and re-using a particular “selection”, which, considering the verbosity of some range phrases, is not trivial. Either can be used as part of the definition of the other (that is, a group may be defined using one or more named ranges, and vice versa).

However, there is a critical difference. A named range is a stored range phrase: a set of criteria for selecting model objects. It may return different results at different times, depending on the behavior of the model and the definition of the range. Also, a named range can be applied to different types of objects. A group is always a collection of a specific set of objects of a specific type that will change only if group members are explicitly added, moved, or deleted.