On the use of virtual reality in software visualization: The case of the city metaphor

Background: Researchers have been exploring 3D representations for visualizing software. Among these representations, one of the most popular is the city metaphor, which represents a target object-oriented system as a virtual city. Recently, this metaphor has been also implemented in interactive software visualization tools that use virtual reality in an immersive 3D environment medium. Aims: We assessed the city metaphor displayed on a standard computer screen and in an immersive virtual reality with respect to the support provided in the comprehension of Java software systems. Method: We conducted a controlled experiment where we asked the participants to fulfill program comprehension tasks with the support of (i) an integrated development environment (Eclipse) with a plugin for gathering code metrics and identifying bad smells; and (ii) a visualization tool of the city metaphor displayed on a standard computer screen and in an immersive virtual reality. Results: The use of the city metaphor displayed on a standard computer screen and in an immersive virtual reality significantly improved the correctness of the solutions to program comprehension tasks with respect to Eclipse. Moreover, when carrying out these tasks, the participants using the city metaphor displayed in an immersive virtual reality were significantly faster than those visualizing with the city metaphor on a standard computer screen. Conclusions: Virtual reality is a viable means for software visualization.