Proceedings: GI 2003

The Effects of Dynamic Transparency on Targeting Performance

Carl Gutwin, Jeff Dyck, Chris Fedak

Proceedings of Graphics Interface 2003: Halifax, Nova Scotia, Canada, 11 - 13 June 2003, 105-112

DOI 10.20380/GI2003.13

  • BibTeX

     title = {The Effects of Dynamic Transparency on Targeting Performance},
     author = {Carl Gutwin and Jeff Dyck and Chris Fedak},
     booktitle = {Proceedings of the Graphics Interface 2003 Conference, June 11-13, 2003, Halifax, Nova Scotia, Canada},
     organization = {CIPS, Canadian Human-Computer Communication Society},
     publisher = {Canadian Human-Computer Communications Society and A K Peters Ltd.},
     issn = {0713-5424},
     isbn = {1-56881-207-8},
     location = {Halifax, Nova Scotia},
     url = {},
     year = {2003},
     month = {June},
     pages = {105--112}


We present a gesture-based user interface to Free-Form Deformation (FFD). Traditional interfaces for FFD require the manipulation of individual points in a lattice of control vertices, a process which is both time-consuming and error-prone. In our system, the user can bend, twist, and stretch/squash the model as if it were a solid piece of clay without being unduly burdened by the mathematical details of FFD. We provide the user with a small but powerful set of gesture-based "ink stroke" commands that are invoked simply by drawing them on the screen. The system automatically infers the user's intention from the stroke and deforms the model without any vertex-specific input from the user. Both the stroke recognition and FFD algorithms are executed in real-time on a standard PC.