WebGL-based streaming and presentation of objects with bidirectional texture functions

Museums and Cultural Heritage institutions have a growing interest in presenting their collections to a broader community via the Internet. The photo-realistic presentation of interactively inspectable virtual surrogates is one of the most challenging problems in this field. For this purpose, we seek to employ not only a 3D geometry but also a powerful material representation capable of reproducing the full visual appeal of an object. In this article, we propose a WebGL-based presentation framework in which reflectance information is represented via Bidirectional Texture Functions (BTF). Our approach works out-of-the-box in modern Web browsers and allows for the progressive transmission and interactive rendering of digitized artifacts consisting of 3D geometry and reflectance information. We handle the huge amount of data needed for this representation by employing a novel progressive streaming approach for BTFs, which allows for the smooth interactive inspection of a steadily improving version during the download. We demonstrate an interesting use-case of this technique at a cross section of Cultural Heritage, medical education, and research and provide an evaluation of the capabilities of our framework in the scope of BTF compression and transmission.