Transpoarent Overview Layers

We are developing the idea of transparent overview layers as a way for people to see both the broad overview of a visual scene as well as fine detail. We have a layered a transparent version of the overview atop the viewport: a zoomed in area (the detail) is seen in the foreground, while the complete workspace (the overview) is shown as a semi-transparent background. Our exploratory user studies indicate that people can use this unusual system, where they switch between layers when performing a construction task.

This pipeline construction system lets users select, position and weld 6 types of pipe pieces: welded assemblies act as a single unit. The figure shows one of six overview representations layered atop a scrollable viewport, this one being 70% transparent (others go from 0 - 100% transparency). All overviews show all pipe pieces and where they are located, and the overall appearance of the pipeline as it is being constructed. Both overview and viewport are active: any pipeline piece can be selected and dragged to a new location. Welding is allowed only on the full-sized pieces visible in the viewport layer, which simulates conditions where certain work activities need to be performed in a high fidelity view.

Our findings indicate that people worked best with overviews that were 50-75% transparent. People were also able to shift their focus rapidly between the two views, to the point of initiating an action in the foreground overview layer, and continuing it is the background viewport layer.

Primary Investigators

Donald Cox (Computer Science)
Jasdeep Chugh (Psychology)
Saul Greenberg (Supervisor)


  • Software implementing the transparent overview developed.
  • Paper produced describing the study.

Current Status

  • Completed this phase. However, we are quite interested in continuing this work to use alpha blending techniques and formal user studies.