Wal, Lukke van derBlesinger, PhilipKosinka, JiriFrey, SteffenAurisano, JillianLaramee, Robert S.Nobre, Carolina2025-05-262025-05-262025978-3-03868-273-8https://doi.org/10.2312/eved.20251021https://diglib.eg.org/handle/10.2312/eved20251021Virtual Ray Tracer (VRT) is an educational tool to provide users with an interactive environment for understanding ray-tracing concepts. Extending VRT, we propose Virtual Volume Raycaster (VVRT), an interactive application that allows to view and explore the volume raycasting process in real-time. The goal is to help users-students of scientific visualization and the general public-to better understand the steps of volume raycasting and their characteristics, for example the effect of early ray termination. VVRT shows a scene containing a camera casting rays which interact with a volume. Learners are able to modify and explore various settings, e.g., concerning the transfer function or ray sampling step size. Our educational tool is built with the cross-platform engine Unity, and we make it fully available to be extended and/or adjusted to fit the requirements of courses at other institutions, educational tutorials, or of enthusiasts from the general public. Two user studies demonstrate the effectiveness of VVRT in supporting the understanding and teaching of volume raycasting.Attribution 4.0 International LicenseCCS Concepts: Applied computing → Interactive learning environments; Human-centered computing → Scientific visualization; Computing methodologies → Ray tracingApplied computing → Interactive learning environmentsHuman centered computing → Scientific visualizationComputing methodologies → Ray tracing10.2312/eved.202510219 pages