1. An apparatus for collaborative editing of an electronic model of an engineering object, the apparatus comprising: a model datastore configured to store an electronic model, or a copy thereof, for an engineering object; a change control module configured to enable a user of a plurality of concurrent users to make changes to an editable feature of the engineering object; a partitioning module configured to initiate spatial decomposition of the engineering object in response to selection of the editable feature of the engineering object by the user, wherein spatial decomposition comprises allocating an editing region that encompasses the geometries that are dependent on the editable feature and would be affected by a change to the editable feature; and the change control module further configured to block all other users from making changes to any editable feature corresponding to the new editing region.