Ordering Regions, Excludes and Features
While not strictly enforced, it is recommended that all REGION subsections be listed before any EXCLUDE or FEATURE subsections and that all EXCLUDE subsections be listed before any FEATURE subsections.
It is further recommended that the first REGION subsection be formed by walking the outside boundary of the problem thereby enclosing the entire domain of the problem.
REGIONS defined later are assumed to overlay any previously listed REGIONs, and any properties assigned to a REGION will override properties previously assigned to the domains they overlay.
Regions in 3D Domains
In 3D domains, the above rule is applied in each extrusion surface.