region

 

The region command defines a geometric region from the set of surfaces by logically combining the surface names.

Format

region / region_name / relation_oper surf_name [logic_oper relation_oper surf_name] [...]

 

region Parameters

Parameters

Type/Value

Description/Default

region_name

char*32

Name of new region being defined by combing surfaces.

relation_oper

 

The region is defined by logically combining the surface names with the surface commands. The parentheses operators, ( and ), are used for nesting. Spaces are required as delimiters to separate all operators and operands. Internal interfaces should be included in exactly one region. In the event of conflicting region commands, the one occurring last in the input stream takes precedence.

 

lt

If the surface following is a volume then lt means inside not including the surface of the volume. If the surface is a plane or a sheet lt means the space on the side of the plane or sheet opposite to the normal not including the plane or sheet itself.

 

le

If the surface following is a volume then le means inside including the surface of the volume. If the surface is a plane or a sheet le means the space on the side of the plane or sheet opposite to the normal including the plane or sheet itself.

 

gt

If the surface following is a volume then gt means outside not including the surface of the volume. If the surface is a plane or a sheet gt means the space on the same side of the plane or sheet as the normal not including the plane or sheet itself.

 

ge

If the surface following is a volume then ge means outside including the surface of the volume. If the surface is a plane or a sheet ge means the space on the same side of the plane or sheet as the normal including the plane or sheet itself.

surf_name

char*32

Name of the surface combining.

logic_oper

 

Logical operators used to combine the relation_oper.

 

or

Union of surfaces.

 

and

Intersection of surfaces.

 

not

Complement of surface.
Rules

Interior interfaces must be included in one and only one region.

No two regions may overlap and there must be no voids.

The operators lt, le, gt, and ge can modify a previously defined surface, resulting in a regions.

The operators or, and, and not are applied to regions and mean union, intersection, and complement respectively.

The union of all regions must describe a connected object.

Parentheses are used for nesting. Parentheses are operators.

Spaces are required as delimiters to separate operators and operands.

Examples

region / reg1 / le sphere1 and ( lt plane1 or gt plane2 )

region / reg2 / le sphere1 and ( ge plane1 and le plane2 )