This graduation thesis comprises the use of modern geometry design software in the process of structural design. By implementing parametrically designed geometry and interactively linking 3D computer graphics application software with structural analysis software, tasks involved in structural design (e.g. automatic design data transfer) can be significantly improved. In the first part of the thesis, the basics of NURBS (Non-uniform Rational Basis Spline) mathematical elements are briefly presented, since the here used geometry design software Rhinoceros, and its add-on Grasshopper, are based on the NURBS. In the second part of the thesis examples of parametric geometrical design of simple space frame and shell structures are presented, along with a linking procedure beetwen Rhinoceros and structural analysis software SAP2000. In order to evaluate suitability of structural geometry, several Grasshopper based add-ons were tested out including specific genetic optimization algorithms. The genetic algorithms allow us to find optimal structural geometry due to predefined objective function and constraints. In the final part of the thesis, a new Grasshopper based Rhinoceros-SAP2000 interface/component is introduced which was programmed by using Visual Basic.NET scripting language.