CodeCity: A comparison of on-screen and virtual reality

Context: Over the past decades, researchers proposed numerous approaches to visualize source code. A popular one is CodeCity, an interactive 3D software visualization representing software system as cities: buildings represent classes (or files) and districts represent packages (or folders). Building dimensions represent values of software metrics, such as number of methods or lines of code. There are many implementations of CodeCity, the vast majority of them running on-screen. Recently, some implementations using virtual reality (VR) have appeared, but the usefulness of CodeCity in VR is still to be proven. Aim: Our comparative study aims to answer the question “Is VR well suited for CodeCity, compared to the traditional on-screen implementation?” Methods: We performed two experiments with our web-based implementation of CodeCity, which can be used on-screen or in immersive VR. First, we conducted a controlled experiment involving 24 participants from academia and industry. Taking advantage of the obtained feedback, we improved our approach and conducted a second controlled experiment with 26 new participants. Results: Our results show that people using the VR version performed the assigned tasks in much less time, while maintaining a comparable level of correctness. Conclusion: VR is at least equally well-suited as on-screen for visualizing CodeCity, and likely better.