1 The Semantics of Geometric Constraints.- The Role of Constraints in Geometric Modelling.- Progress and Problems in Extending the STEP Standard.- 2 Constraints for Conceptual and Collaborative Design.- Constraint Propagation Using an Active Semantic Network.- Analyzing and Optimizing Constraint Structures in Complex Parametric CAD Models.- Design Support Using Constraint-Driven Design Spaces.- Solving Over- and Underconstrained Geometric Models.- A Constraint-Based Shape Modeling System.- 3 Constraint Representation and Solving Methods.- Modelling of Geometric Constraints in CAD-Applications.- Geometric Constraint Decomposition.- Desargues: A Constraint-Based System for 3D Projective Geometry.- YAMS: A Multi Agent for 2D Constraint Solving.- Qualitative Study of Geometric Constraints.- Geometric Relaxation for Solving Constraint-Based Models.- 4 Constraints for Freeform Surfaces.- Variational Design and Surface Reconstruction.- Computer Aided Spectacle Lens Design.