Regions in One Dimension
In one-dimensional domains, the concept that a REGION bounds a finite area by closing on itself is no longer true. In one dimension, it is sufficient to define a path from the start of a material region to its finish. (Referencing CLOSE in a 1D bounding path will cause serious troubles, because the path will retrace itself.)
For example, the statements
START(0) LINE TO (5)
are sufficient to define a region of material extending from location 0 to location 5 in the 1D coordinate system.
In order to maintain grammatical consistency with two- and three- dimensional constructs, omitting the parentheses is not permitted.
Other general characteristics of REGIONS remain in force in one-dimensional domains:
Later REGIONS overlay earlier REGIONS, material properties are defined following the REGION keyword, and so forth.