1. A method for providing constraint-based guidance to a designer in a collaborative design environment, the method comprising: receiving signals from designers wherein the signals represent design choices for variables of a design; generating a network of design constraints which represent interactions among the variables of the design; evaluating the network of design constraints to obtain conflict information in response to the signals; and transmitting signals to designers affected by the conflict information to provide constraint-based guidance to the affected designers in the collaborative design environment.