Ankara : The Department of Computer Engineering and Information Sciences and the Institute of Engineering and Science of Bilkent Univ. , 1989. Thesis (Master's) -- Bilkent University, 1989. Includes bibliographical references leaves 46-48. One of the most important problems of available solid modeling systems is that the range of shapes generated is limited. It is not easy to model objects with free-form surfaces in a conventional solid modeling system. Such objects can be defined arl^itrarily but then operations on them are not transparent and complications occur. A method for achieving free-form effect is to define regular objects or surfaces, then deform them. This keeps various properties of the model intact while achieving the required visuaJ appearance. This thesis explains a number of geometric modeling techniques with deformations applied to them in attempts to combine various approaches developed so far. Regular deformations, which include twisting, bending, and tapering, and free-form deformation technique are combined as a new deformation method. This eliminates some of the disadvantages peculiar to each method and utilizes the advantages of both. Güdükbay, Uğur M.S.