Abstract
A geometric model can be made in the digital space by applying a certain rule and parametric modeling is made for regular transformation of the geometric model. Parametric modeling is divided into a constraint-based model and a propagation-based. A constraint-bases model applies regular architectural elements to the formal design and a propagation-based model applies irregular extensible model to its design. A software program which can transform a Voronoi diagram on the base of constraint-based BIM into the ArchiCAD geometric GDL language. Converted coordinates with GDL commands can make a parametric Voronoi diagram and make it possible to express creative design thinkings. And by considering a parametric automatic connection and connectivity, relations between the geometric parametric modeing and the topology were identified.