A method comprising: obtaining a first viewpoint representing a partial depiction of a system, wherein the first viewpoint comprises a property base, an instance base and a class base; obtaining a second viewpoint representing a partial depiction of the system, wherein the second viewpoint comprises a property base, an instance base and a class base, wherein the instance base of the second viewpoint is different than the instance base of the first viewpoint; creating a third viewpoint based on the first and second viewpoints, wherein the third viewpoint representing the system, wherein the third viewpoint comprises a property base, an instance base and a class base, wherein the instance base comprises instances defined by the instance base of the first viewpoint and instances defined by the instance base of the second viewpoint.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method comprising: obtaining a first viewpoint representing a partial depiction of a system, wherein the first viewpoint comprises a property base, an instance base and a class base; obtaining a second viewpoint representing a partial depiction of the system, wherein the second viewpoint comprises a property base, an instance base and a class base, wherein the instance base of the second viewpoint is different than the instance base of the first viewpoint; creating a third viewpoint based on the first and second viewpoints, wherein the third viewpoint representing the system, wherein the third viewpoint comprises a property base, an instance base and a class base, wherein the instance base comprises instances defined by the instance base of the first viewpoint and instances defined by the instance base of the second viewpoint. 2. The method of claim 1, wherein the property base comprises a specification of a set of properties of the viewpoint and a specification of a set of property relationships in the viewpoint. 3. The method of claim 2, wherein the class base comprises a specification of a set of classes, wherein each class is specified using some of the properties in the property base, wherein an instance is associated with a class of the class base based on properties of the instance as defined in the instance base. 4. The method of claim 3, wherein the class base comprises a specification of a core set of properties, wherein the core set of properties are used to uniquely identify an instance in a viewpoint. 5. The method of claim 1, wherein the first viewpoint is obtained from a first designing tool having a first knowledge base, wherein the second viewpoint is obtained from a second designing tool having a second knowledge base. 6. The method of claim 5 further comprises: in response to the first designing tool updating the first knowledge base, receiving an updated first viewpoint and updating the third viewpoint. 7. The method of claim 6 further comprises: in response to said updating the third viewpoint, updating the second viewpoint based on the updated third viewpoint. 8. The method of claim 5 further comprising: in response to the first designing tool performing a query on the first knowledge base, intercepting the query and providing a response to the query based on the third viewpoint. 9. A computerized apparatus having a processor, the processor being adapted to perform the steps of: obtaining a first viewpoint representing a partial depiction of a system, wherein the first viewpoint comprises a property base, an instance base and a class base; obtaining a second viewpoint representing a partial depiction of the system, wherein the second viewpoint comprises a property base, an instance base and a class base, wherein the instance base of the second viewpoint is different than the instance base of the first viewpoint; creating a third viewpoint based on the first and second viewpoints, wherein the third viewpoint representing the system, wherein the third viewpoint comprises a property base, an instance base and a class base, wherein the instance base comprises instances defined by the instance base of the first viewpoint and instances defined by the instance base of the second viewpoint. 10. The computerized apparatus of claim 9, wherein the property base comprises a specification of a set of properties of the viewpoint and a specification of a set of property relationships in the viewpoint. 11. The computerized apparatus of claim 10, wherein the class base comprises a specification of a set of classes, wherein each class is specified using some of the properties in the property base, wherein an instance is associated with a class of the class base based on properties of the instance as defined in the instance base. 12. The computerized apparatus of claim 11, wherein the class base comprises a specification of a core set of properties, wherein the core set of properties are used to uniquely identify an instance in a viewpoint. 13. The computerized apparatus of claim 9, wherein the first viewpoint is obtained from a first designing tool having a first knowledge base, wherein the second viewpoint is obtained from a second designing tool having a second knowledge base. 14. The computerized apparatus of claim 13, wherein the processor is further adapted to perform: in response to the first designing tool updating the first knowledge base, receiving an updated first viewpoint and updating the third viewpoint. 15. The computerized apparatus of claim 14, wherein the processor is further adapted to perform: in response to said updating the third viewpoint, updating the second viewpoint based on the updated third viewpoint. 16. The computerized apparatus of claim 13, wherein the processor is further adapted to perform: in response to the first designing tool performing a query on the first knowledge base, intercepting the query and providing a response to the query based on the third viewpoint. 17. A computer program product comprising a computer readable storage medium retaining program instructions, which program instructions when read by a processor, cause the processor to perform a method comprising: obtaining a first viewpoint representing a partial depiction of a system, wherein the first viewpoint comprises a property base, an instance base and a class base; obtaining a second viewpoint representing a partial depiction of the system, wherein the second viewpoint comprises a property base, an instance base and a class base, wherein the instance base of the second viewpoint is different than the instance base of the first viewpoint; creating a third viewpoint based on the first and second viewpoints, wherein the third viewpoint representing the system, wherein the third viewpoint comprises a property base, an instance base and a class base, wherein the instance base comprises instances defined by the instance base of the first viewpoint and instances defined by the instance base of the second viewpoint.