Dynamic Label Placement for Forensic Case Visualization C. Sirk †1 D. Kalkofen 2 D. Schmalstieg 2 A. Bornik 3 1 Graz University of Technology, Graz, Austria 2 Institute for Computer Graphics and Vision (ICG), Graz University of Technology, Graz, Austria 3 Ludwig Boltzmann Institute – Clinical-Forensic Imaging (CFI), Graz, Austria (a) (b) (c) Figure 1: Label placement in forensic scenes: Annotated stabbing case visualization based on CT data. Overview frame (a) and close-up view (b) from an interactive exploration of the stab wound. (c) Case illustration showing an unusual bullet path based on CT data, and meshes for weapon, expected, and actual bullet path. Our approach is able to integrate both, polyhedral model and volume rendering. Abstract Forensic case analysis and in court presentation requires comprehensible illustrations and animations of findings and their re- lations to the course of events. Often this can only be achieved by adding textual descriptions. From a systems point of view, this requires automated label placement functionality for scenes composed of translucent polyhedral models and volumes, which we achieve through tight integration of the automated label placement algorithm and the hybrid volume/surface rendering system. Our method exploits transparency in order to place labels close to their anchors, either inside the scene, on-top or outside the occupied screen region. Inside placement makes it possible to zoom into the dataset, leads to more temporal coherency, and improves layout quality, especially for large numbers of labels. New measures for scene content importance and label occlusion prevent masking of important scene details by labels and vice versa. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Label Placement, Volume Rendering 1. Introduction Comprehensible visualization of forensic data is a challenging task. Volumetric scans of inner injuries have to be presented to judges, juries and lawyers without the medical and anatomical background required to understand findings and their connection to the course † This project is financed by the KIRAS programme (no. 850183, CSIS- martScan3D) under supervison of the Austrian Research Promotion Agency (FFG). of events from the medical data itself. Therefore, forensic presen- tation aims at largely self-explanatory illustrations, depicting indi- vidual findings and explaining them and their expert interpretations using text labels. Presentation in form of videos and interactive de- mos further aids case understanding, but requires automated label placement. Forensic case illustration needs combine different types of data like CT volumes and polyhedral models like 3D scans of weapons. Moreover, forensic scenes exhibit a high degree of transparency to be able to depict spatial relations between exterior and interior find- c  2017 The Author(s) Eurographics Proceedings c  2017 The Eurographics Association. Eurographics Conference on Visualization (EuroVis) 2017 Short Paper B. Kozlíková, T. Schreck, and T. Wischgoll (Editors) DOI: 10.2312/eurovisshort.20171147