Coupling two constraint-based systems into an on-line facade-layout configurator

We present the coupling of two constraint-based environments into an on-line support system for façade-layout configuration in the context of building renovation. The configuration consist on the definition and allocation of a set of rectangular parameterizable panels over a façade surface. The coupling allows to solve two configuration tasks while gaining efficiency and modularity. First, it allows to configure a set of questions relating the renovation model needed to determine limits for panels’ size and panels’ weight. Second, it allows to configure a constraint satisfaction model for each of the façades to renovate. Two constraint-based systems handle the filtering of incompatible values and the generation of layout plans in a web-service setup. The first service performs initial filtering to set panels’ limits, based on the questionnaire, using a constraint filtering engine called CoFiADe. The second service uses several façadelayout configuration algorithms, using as underlying engine the constraint solver Choco, to generate compliant layout-plan solutions. We show that by dividing filtering and search, and by coupling the two constraint-based systems, we gain modularity and efficiently as each service focuses on their own strengths. Services executing tasks may be hosted in different network-nodes and thus may be seen as independent communicating agents.