The exterior boundary surface of the volume. Defines theouter shell that encloses the three-dimensional feature. For solidvolumes, this is the only boundary surface needed.
Interior boundary surfaces (voids or holes) within thevolume. Defines hollow spaces or cavities inside thethree-dimensional feature. Multiple interior boundaries can bespecified for complex geometries with multiple voids. Optional - notneeded for solid volumes without internal voids.
diggs:AbstractSolidType is an abstraction of a solid to support thedifferent levels of complexity. The solid may always be viewed as a geometricprimitive, i.e. is continuous.
Database handle for the object. It is of XML type ID, so is constrained to beunique in the XML document within which it occurs. An external identifier for the object inthe form of a URI may be constructed using standard XML and XPointer methods. This is doneby concatenating the URI for the document, a fragment separator, and the value of the idattribute.