Modeling, Rendering, 3D Printing


Increasing computer power together with new developments in 3D hardware and fast algorithms for geometry optimization have opened the door to extremely complex virtual environments that can now be displayed at interactive speed. But still, with traditional modeling technology, industrial 3D construction is typically quite time consuming and, thus, very expensive. As every object is basically unique, the created models suffer from two main problems, poor changeability and poor reusability of 3D models. Detailed models are typically designed on a part-by-part basis to reduce the modeling complexity. But then, many dependency relations between geometric entities within the 3D scene get lost. As these relations cannot be expressed explicitly, it is not possible to alter them directly. This conceptual limitation abates both changeablity and reusability, as even a slightly different object may require many construction steps to be repeated in a different fashion.

Generative Modeling

Many steps in the modeling process are repeated several times with different parameters on different objects. Consequently, it is desirable to automate 3D modeling using some form of geometric programming language. When a user can specify variables and functions in a geometric program to let object parameters be computed automatically, even dynamic models become possible. Programmed models have a different space-time tradeoff: When low-level primitives are generated only on demand from higher-level descriptions, space is traded for model evaluation complexity. With a geometric modeling language that permits compact and comprehensive descriptions of very detailed models, this model description has to be quickly translated to graphics primitives at runtime. This leads to the following research directions:

  • language-based 3D-modeling
  • efficient model evaluation and visualization

In fact, this approach initiates a paradigm change from traditional object-based modeling to function-based, i.e. generative, modeling. Objects are not described in terms of triangles anymore, but merely in terms of the function.


Prof. Fellner’s memberships in TUD activities are:


  • D. W. Fellner, S. Havemann, G. Müller, Modeling of and Navigation in Complex 3D Documents: Computers & Graphics, Vol. 22, No. 6, Dec 1998
  • K. Müller, S. Havemann: Subdivision Surface Tesselation on the fly using a versatile Mesh Data Structure, Computer Graphics Forum, Vol. 19, No. 3, Aug. 2000
  • D. W. Fellner et al.: Beiträge der Computergraphik zur Realisierung eines verallgemeinerten Dokumentenbegriffs, it+ti 6/2000