In this paper we introduce LUCI, a Leightweight Urban Calculation Interchange system, designed to bring the advantages of calculation and content co-ordination system to small planning and design groups by the means of an open source middle-ware.The middle-ware focuses on problems typical to urban planning and therefore features a geo-data repository as well as a job runtime administration, to coordinate simulation models and its multiple views.The described system architecture is accompanied by two exemplary use cases, that have been used to test and further develop our concepts and implementations
