Constraint management plays an important role in design
applications where constraints reect design restrictions and
design decisions. ECA rules are a widely used mechanism to
enforce constraints. The paper argues that such rules must be
augmented for design environments by a spatial and a temporal
dimension of validity, resulting in so-called
area-event-condition-action (AECA) rules. The spatial dimension
allows to restrict constraints locally in the design space, and
to control interaction between designers. The temporal dimension
permits designers to retract their designs to earlier stages.
The paper introduces the concept of AECA rules, motivates them
by examples from building design, discusses rule management, and
then introduces two important issues, conflict detection during
collaboration, and backtracking during design revision.