to generate VSS, and how they can be used to convey the depth of vascular structures by applying the most commonly used depth cues, such as chromadepth, pseudo-chromadetph, occlusions, or dark-means-deep to these surfaces. To demonstrate the capabilities of VSS, we further have conducted a user study in which we compared VSS with previous vessel visualization techniques. Thus, our contributions are threefold:

-   First, we introduce *Void Space Surfaces* (VSS), a novel vessel visualization technique that improves the depth perception of complex vascular structures without interfering with the color channel used to communicate a vessel’s geometry.

-   Second, we show how VSS can be used as a canvas for well established depth cues, and thus leave room on the vessel’s surface to communicate additional vessel parameters.

-   Third, we report the results of a user study, which we have conducted in order to analyze the perceptual benefits of VSS as compared to previous vessel visualization techniques.

The remainder of this paper is structured as follows. After having discussed related work in Section \[sec:relatedwork\] we describe general design goals for vessel visualizations, which have motivated our approach, in Section \[sec:designgoals\]. VSS are then introduced in Section \[sec:vss\] where we also show 