BxDF material acquisition, representation, and rendering for VR and design

BxDF material acquisition, representation, and rendering for VR and design

Photorealistic and physically-based rendering of real-world environments with high fidelity materials is important to a range of applications, including special effects, architectural modelling, cultural heritage, computer games, automotive design, and virtual reality (VR). Our perception of the world depends on lighting and surface material characteristics, which determine how the light is reflected, scattered, and absorbed. In order to reproduce appearance, we must therefore understand all the ways objects interact with light, and the acquisition and representation of materials has thus been an important part of computer graphics from early days. Nevertheless, no material model nor acquisition setup is without limitations in terms of the variety of materials represented, and different approaches vary widely in terms of compatibility and ease of use. In this course, we describe the state of the art in material appearance acquisition and modelling, ranging from mathematical BSDFs to data-driven capture and representation of anisotropic materials, and volumetric/thread models for patterned fabrics. We further address the problem of material appearance constancy across different rendering platforms. We present two case studies in architectural and interior design. The first study demonstrates Yulio, a new platform for the creation, delivery, and visualization of acquired material models and reverse engineered cloth models in immersive VR experiences. The second study shows an end-to-end process of capture and data-driven BSDF representation using the physically-based Radiance system for lighting simulation and rendering.

对具有高保真材质的现实世界环境进行逼真的、基于物理的渲染，对于一系列应用至关重要，包括特效、建筑建模、文化遗产、电脑游戏、汽车设计以及虚拟现实（VR）。我们对世界的感知取决于光照和表面材质特性，这些特性决定了光线如何反射、散射和吸收。因此，为了重现外观，我们必须了解物体与光线相互作用的所有方式，并且材质的获取和表示从早期开始就是计算机图形学的一个重要部分。然而，就所表示的材质种类而言，没有任何一种材质模型或获取设置是没有局限性的，而且不同的方法在兼容性和易用性方面差异很大。在本课程中，我们描述了材质外观获取和建模方面的最新技术，从数学的双向散射分布函数（BSDF）到各向异性材质的数据驱动捕获和表示，以及用于有图案织物的体积/线条模型。我们进一步解决了不同渲染平台之间材质外观一致性的问题。我们展示了两个在建筑和室内设计方面的案例研究。第一项研究展示了Yulio，这是一个用于在沉浸式VR体验中创建、交付和可视化所获取的材质模型以及逆向工程布料模型的新平台。第二项研究展示了一个使用基于物理的Radiance系统进行光照模拟和渲染的捕获和数据驱动的BSDF表示的端到端流程。