Automated Acquisition and Real-time Rendering of Spatially Varying Optical Material Behavior Martin Ritz Cultural Heritage Digitization Fraunhofer IGD martin.ritz@igd.fraunhofer.de Pedro Santos Cultural Heritage Digitization Fraunhofer IGD pedro.santos@igd.fraunhofer.de Dieter Fellner Fraunhofer IGD, TU Darmstadt, TU Graz dieter.fellner@gris.tu-darmstadt.de Figure 1: 3D rendering: two measured ABTF materials for diferent virtual light directions (samples courtesy of Foster+Partners). ABSTRACT We created a fully automatic system for acquisition of spatially varying optical material behavior of real object surfaces under a hemisphere of individual incident light directions. The resulting measured material model is fexibly applicable to arbitrary 3D model geometries, can be photorealistically rendered and interacted with in real-time and is not constrained to isotropic materials. CCS CONCEPTS · Computing methodologies → Refectance modeling; Tex- turing; Physical simulation; Perception; Graphics fle formats; KEYWORDS ABTF, optical material behavior acquisition, texture synthesis ACM Reference Format: Martin Ritz, Pedro Santos, and Dieter Fellner. 2018. Automated Acquisition and Real-time Rendering of Spatially Varying Optical Material Behavior. In Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for proft or commercial advantage and that copies bear this notice and the full citation on the frst page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). SIGGRAPH ’18 Posters, August 12-16, 2018, Vancouver, BC, Canada © 2018 Copyright held by the owner/author(s). ACM ISBN 978-1-4503-5817-0/18/08. https://doi.org/10.1145/3230744.3230806 Proceedings of SIGGRAPH ’18 Posters. ACM, New York, NY, USA, 2 pages. https://doi.org/10.1145/3230744.3230806 1 INTRODUCTION AND MOTIVATION Photorealism in 3D rendering is continuously gaining more impor- tance as it expands across diferent felds of applications, including 3D games industry and all areas where rapid prototyping is used already in early design stages, such as in the automotive and textile industry. But where do the specifcations come from that defne realistic materials? Manual design of material models is one way, having been applied for a long time and perfected to deliver quite realistic material behaviors. The only way, however, to bring out the physically correct light interaction behavior for each individ- ual - or a mixture of diferent - materials on a surface, is actual measurement under systematic illumination from a set of diferent perspectives to reveal the actual optical reaction. One reason to go this far is material behavior faithful to reality, and individual rather than abstract classes of materials. Another reason is damage assessment, e.g. for industrial quality control. 2 TECHNICAL APPROACH We have developed such a measurement setup, and it is fully auto- matic. There is a wide range of material models that can be physi- cally acquired, ranging from BRDFs (Bi-directional Refectance Dis- tribution Functions) to BTFs (Bi-directional Texturing Functions)