Abstract
We describe a tool for generating Euler diagrams from a set of region connection calculus formulas. The generation is based on a variant of local search capturing default reasoning for improving aesthetic appearance of Euler diagrams. We also describe an optimization for diagrams to be interactive: the user can modify the diagram with the mouse while formulas are still satisfied. We also discuss how such a tool may propose new relevant formulas to add to the specification using an approximation algorithm based on the satisfiability of Horn clauses.