Kuß, AnjaGensel, MariaMeyer, BjörnDercksen, Vincent J.Prohaska, SteffenG. Melancon, T. Munzner, and D. Weiskopf2014-02-212014-02-2120101467-8659https://doi.org/10.1111/j.1467-8659.2009.01703.xCombined visualizations of filamentous structures and surrounding volumetric objects are common in biological and medical applications. Often, the structures spatial relationships remain unclear to the viewer. In this paper, we discuss and evaluate techniques to emphasize spatial relationships. We concentrate on the visualization of transparent objects and intersecting lines. Among various techniques, participants of an exploratory user study preferred coloring of lines, marking of line-surface intersections by glyphs, and the combination of both. These techniques were additionally evaluated in a confirmatory study in which participants were asked to judge whether a filament runs through a transparent structure. We found that the evaluated techniques significantly improve the participants performance in terms of the number of correct responses and response time. The best performance was found for the combination of line coloring and intersection glyph display.