This operator returns 1 if the specified point or primitive number is in the group specified by the string. It returns 0 if the group does not exist or the element is not contained in the group.
The file on disk to fetch the geometry from.
The name of the point or primitive group.
Specifies whether the group is a point or primitive group.
Point or Primitive
When the class is point, this will be the point number to test group membership for. If the class is primitive, it is the primitive number.