The AcBr::ValidationLevel enum sets the level of validation for an AcBr object. If kFullValidation (the default upon object instantiation) is specified, every function that accesses the brep topology (directly or indirectly) first checks the associated AutoCAD database object to see if it has been modified since the AcBr object was last set. This is an expensive operation, but it guarantees all brep data is within scope. If kNoValidation is specified, the database is not checked unless it is critical to the completion of the function's tasks. This is more efficient but does not guarantee the brep data is within scope. Setting the validation level on an object-by-object basis prevents any collisions between applications loaded simultaneously.