Consistency maintenance based on the matching of topological entity

Consistency maintenance is one of the most important problems in collaborative CAD systems. However, existing consistency maintenance mechanisms limit multi-user interaction. This paper presents a consistency maintenance method to gain a less-constrained multi-user interaction. First, the causal relation between modeling operations is preserved using the state vector. Then, the concurrent deletion operations are checked to decide if the current operation is masked. If not, the solution for topological entities´ matching is adopted to deal with the operations that use topological entities. Then, for those operations which do not use topological entities, the corresponding mechanism is adopted according to their types. By these mechanisms, the commutative, masked and conflicted relations between the concurrent operations, are explored and the conflicts are solved. The experiments prove that our method can support less-constrained multi-user interaction.