.
OPENNPAR: A System for Developing, Programming, and Designing Non-Photorealistic Animation and Rendering
Nick Halper, Tobias Isenberg, Felix Ritter, Bert Freudenberg, Oscar E. Meruvia Pastor, Stefan Schlechtweg, Thomas Strothotte.
11th Pacific Conference on Computer Graphics and Applications (PG'03), pp. 424, Canmore, Canada,
2003. [BibTeX]
Real-Time Illustration of Vascular Structures
Felix Ritter, Christian Hansen, Volker Dicken, Olaf Konrad-Verse, Bernhard Preim, Heinz-Otto Peitgen.
IEEE Transactions on Visualization and Computer Graphics, Vol. 12, No. 5, pp. 877--884,
2006. [BibTeX]
Using a 3D Puzzle as a Metaphor for Learning Spatial Relations
Author(s): Felix Ritter, Bernhard Preim, Oliver Deussen, Thomas Strothotte.
Proceedings: Graphics Interface (GI'00), Montreal, 15-17 May,
2000.
[BibTeX] 
Abstract:
We introduce a new metaphor for learning spatial relations—
the 3D puzzle. With this metaphor users learn
spatial relations by assembling a geometric model themselves.
For this purpose, a 3D model of the subject at
hand is enriched with docking positions which allow objects
to be connected. Since complex 3D interactions are
required to compose 3D objects, sophisticated 3D visualization
and interaction techniques are included.
Among these techniques are specialized shadow generation,
snapping mechanisms, collision detection and the
use of two-handed interaction.
The 3D puzzle, similar to a computer game, can be
operated at different levels of difficulty. To simplify the
task, a subset of the geometry, e.g., the skeleton of an anatomic
model, can be given initially. Moreover, textual
information concerning the parts of the model is provided
to support the user. With this approach we motivate
students to explore the spatial relations in complex
geometric models and at the same time give them a goal
to achieve while learning takes place. A prototype of a
3D puzzle, which is designed principally for use in anatomy
education, is presented.