The Manifold attribute (0066,0010) shall be YES when the surface mesh is a manifold.
A surface embedded into an n-dimensional vector space is called an n-1 manifold if it resembles an n-1 dimensional Euclidian space in a neighborhood of every point lying on the surface. This means that every point has a neighborhood for which there exists a homeomorphism mapping that neighborhood to the n-1 dimensional Euclidian space.
A sphere in 3-space is a 2-dimensional manifold: Every point has a neighborhood that looks like a plane.
Figure C.27.1.1-2 shows examples of a surface that is not a manifold is given below:
Figure C.27.1.1-2 - Manifold Illustration
A value of NO indicates that the surface is not a manifold.
A value of UNKNOWN indicates that the transmitting application did not determine if the surface is a manifold.