Summary: Employing Dynamic Transparency for
3D Occlusion Management:
Design Issues and Evaluation
Abstract. Recent developments in occlusion management for 3D envi-
ronments often involve the use of dynamic transparency, or virtual "X-
ray vision", to promote target discovery and access in complex 3D worlds.
However, there are many different approaches to achieving this effect and
their actual utility for the user has yet to be evaluated. Furthermore, the
introduction of semi-transparent surfaces adds additional visual com-
plexity that may actually have a negative impact on task performance.
In this paper, we report on an empirical user study comparing dynamic
transparency to standard viewpoint controls. Our implementation of the
technique is an image-space algorithm built using modern programmable
shaders to achieve real-time performance and visually pleasing results.
Results from the user study indicate that dynamic transparency is supe-
rior for perceptual tasks in terms of both efficiency and correctness.
The ability to utilize the full 3D space as a canvas for information-rich  vi-
sualization applications is a mixed blessing--while 3D space on the one hand
supports an order of magnitude of more layout opportunities for visual elements