Searching for a unified scene representation remains a research challenge in computer graphics. Traditional mesh-based representations are unsuitable for dense, fuzzy elements, and introduce additional complexity for filtering and differentiable rendering. Conversely, voxel-based representations struggle to model hard surfaces and suffer from intensive memory requirement. We propose a general-purpose rendering primitive based on 3D Gaussian distribution for unified scene representation, featuring versatile appearance ranging from glossy surfaces to fuzzy elements, as well as physically based scattering to enable accurate global illumination. We formulate the rendering theory for the primitive based on non-exponential transport and derive efficient rendering operations to be compatible with Monte Carlo path tracing. The new representation can be converted from different sources, including meshes and 3D Gaussian splatting, and further refined via transmittance optimization thanks to its differentiability. We demonstrate the versatility of our representation in various rendering applications such as global illumination and appearance editing, while supporting arbitrary lighting conditions by nature. Additionally, we compare our representation to existing volumetric representations, highlighting its efficiency to reproduce details.

翻译：在计算机图形学领域，寻求一种统一的场景表示方法仍是一个研究挑战。传统的基于网格的表示方法不适用于密集、模糊的元素，并且为滤波和可微渲染引入了额外的复杂性。反之，基于体素的表示方法难以建模硬表面，并且面临巨大的内存需求。我们提出了一种基于三维高斯分布的通用渲染基元，用于统一的场景表示，其特点在于能够呈现从光泽表面到模糊元素的多样化外观，并支持基于物理的散射以实现精确的全局光照。我们基于非指数传输理论为该基元构建了渲染理论，并推导出高效的渲染操作，使其与蒙特卡洛路径追踪兼容。这种新的表示可以从不同来源（包括网格和三维高斯泼溅）转换而来，并借助其可微性通过透射率优化进一步细化。我们在全局光照和外观编辑等多种渲染应用中展示了我们表示的通用性，同时其本质支持任意光照条件。此外，我们将我们的表示与现有的体表示进行了比较，突显了其在复现细节方面的高效性。