卢卡斯影业

OpenPBR is a physically based, standardized uber-shader developed for interoperable material authoring and rendering across VFX, animation, and design visualization workflows. This document serves as a companion to the official specification, offering deeper insight into the model's development and more detailed implementation guidance, including code examples and mathematical derivations. We begin with a description of the model's formal structure and theoretical foundations - covering slab-based layering, statistical mixing, and microfacet theory - before turning to its physical components. These include metallic, dielectric, subsurface, and glossy-diffuse base substrates, followed by thin-film iridescence, coat, and fuzz layers. A special-case mode for rendering thin-walled objects is also described. Additional sections explore technical topics in greater depth, such as the decoupling of specular reflectivity from transmission, the choice of parameterization for subsurface scattering, and the detailed physics of coat darkening and thin-film interference. We also discuss planned extensions, including hazy specular reflection and retroreflection.

LED volume virtual production brings its own unique set of challenges that differ from typical applications of real-time rendering. ILM StageCraft is a complete suite of virtual production tools that incorporates powerful off-the-shelf systems, such as Unreal, with proprietary solutions that allow us to overcome these challenges—always with the goal of using the very best tool for the job. To meet the most demanding requirements for The Mandalorian season 2 and beyond, Industrial Light & Magic (ILM) developed and augmented proprietary technology solutions in StageCraft 2.0, including a new real-time rendering engine, Helios, and a collection of interactive tools that give filmmakers the freedom, creative feedback, and real-time control to make immediate adjustments on set. Powered by ILM’s award-winning set of tools focused on rendering, lighting, and color, creatives can achieve their desired looks and goals without having to wait for traditional post-production or DI to take place. Since season 2 of The Mandalorian, ILM has continued to evolve the Helios renderer, expanding what’s possible not only in terms of visual fidelity but also visual adjustability, through a real-time toolset that allows on-set operators to rapidly respond (in a matter of seconds!) to late-breaking changes in creative direction, in ways that make intuitive sense for filmmakers rather than technologists and gamers. This groundbreaking approach saves significant time on set while also providing greater creative control and insights over the final result, allowing for an unprecedented degree of freedom and flexibility to make the right choices on the day. This talk will address why, in today’s landscape, you would even consider writing a set of proprietary tools and renderer. It will cover the various aspects of ILM StageCraft rendering and operations, from the streaming systems that feed the Helios renderer, to the core rendering passes (geometry submission, direct lighting, ray-traced reflections, volumetrics, etc.) that compose a frame, as well as the various controls we provide for on-the-day tweaks to virtual content. Along the way, we will discuss our integrated and seamless color pipeline that provides end-to-end confidence in the quality of the captured results. We will also point out some gotchas with using established real-time rendering techniques in the context of the LED volume and how we overcame them. Finally, we will touch on how ILM StageCraft fits within the larger picture of visual effects production and where we plan to take it in the future.

Some Thoughts on the Fresnel Term Naty Hoffman The Fresnel term would appear to be the best-understood part of the microfacet model --- one can simply use the original equations, or an approximation (usually Schlick's) if computation cost is at a premium. However, in this talk, we will show that all is not as it seems, and that even the humble Fresnel term can hold some surprises. This talk builds on a previous presentation at the 2019 Eurographics Workshop on Material Appearance Modeling [Hof19], extending it into a more comprehensive overview.

No abstract available.