We want any non-3D tool users to be able to configure their 3D world, experiment and plan their day-to-day projects, such as plan a new office, renovate their kitchen or lay out landscape.

People manipulate real world objects based on law of physics, i.e. gravity and friction. The system allows users to create a geometry and immediately then, the rule of manipulating the object follows the "virtual" gravity and friction defined by the system.


This was my Ph.D. thesis project that led me to the profession of UX design. I built the system ground up, performed usability studies, came up with new algorithms, published papers.


Academic research, usability, C++, OpenGL, and variety of libraries involving mesh creation, sketch recognition, and collision detection.

Sample scene created from the tool I developed for my Ph.D. thesis

Sample scene created from the tool I developed for my Ph.D. thesis


How to provide a natural object motion that allow users to place an object at the intended location using a 2D input device.


I iteratively built the tool, perform informal usability tests, and then built again based on the feedback and observation. The usability sessions revealed that people try to place an object by trying to overlapping 2D projection of the 3D object with the 2D projection of background world. We applied this observation to identify the target location of a 3D object.


We performed usability tests with simple chair assembly task. The results showed that the average task completion time using the new algorithm was three times faster than the industry standard triad approach. The new algorithm works for any type of geometry, not just the planar surface, since the location of 3D object is calculated based off of pixels, rather than semantic relationships or heuristics based on planar objects. The video demonstrates the point.


Ji-Young Oh, Wolfgang Stuerzlinger, A System for Desktop Conceptual 3D Design, Virtual Reality 2004, 7(3-4): 198-211.

Ji-Young Oh, Wolfgang Stuerzlinger, J. Danahy, SESAME: Towards Better 3D Conceptual Design Systems, ACM Conference on Designing Interactive Systems, June 2006: 80-89. (citation: 17)

Ji-Young Oh, Wolfgang Stuerzlinger, D. Dadgari, Group Selection Techniques for Efficient 3D Modeling, IEEE Symposium on 3D User Interfaces 2006, March 2006: 95-102.

Ji-Young Oh, Wolfgang Stuerzlinger, J. Danahy, Comparing SESAME and Sketching for Conceptual 3D Design, Eurographics Workshop on Sketch Based Interfaces and Modeling, Aug. 2005: 81- 88.

Ji-Young Oh, Wolfgang Stuerzlinger, Moving Objects with 2D Input Devices in CAD Systems and Desktop Virtual Environments, Graphics Interface 2005: 195-202. (citation: 33)

Ji-Young Oh, Wolfgang Stuerzlinger, Intelligent Manipulation Techniques for Conceptual 3D Design, IFIP Interact 2003, Sept. 2003: 319-326. (citation:8)

Wolfgang Stuerzlinger, Darin Dadgari, Ji-Young Oh, Reality-Based Object Movement Techniques for 3D, CHI 2006 Workshop: “What is the Next Generation of Human-Computer Interaction?” April 2006.

Ji-Young Oh, Grouping Techniques for 3D Conceptual Design, ACM Symposium on User Interface Software and Technology (UIST) 2004 Doctoral Symposium.

Ji-Young Oh, Wolfgang Stuerzlinger, SESAME: A 3D Conceptual Design System, ACM International Conference on Computer Graphics and Interactive Techniques (SIGGRAPH) 2004 Poster.