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.s
在计算机图形学中，寻找统一的场景表示仍是一个研究挑战。传统的基于网格的表示法不适用于密集、模糊的元素，并且在过滤和可微渲染方面引入了额外的复杂性。相反，基于体素的表示法难以模拟硬表面，并且会遭受密集的内存需求。我们提出了一种基于三维高斯分布的通用渲染原语，用于统一场景表示，具有从光滑表面到模糊元素的多样化外观，以及基于物理的散射，以实现准确的全局照明。我们根据非指数传输公式化了该原语的渲染理论，并推导出与蒙特卡罗路径跟踪兼容的高效渲染操作。这种新的表示法可以从不同来源转换，包括网格和三维高斯平涂，且由于其可微性，可以通过透射优化进一步细化。我们展示了我们的表示在各种渲染应用中的多功能性，如全球照明和外观编辑，同时自然地支持任意光照条件。此外，我们将我们的表示与现有的体积表示进行比较，突出其在复制细节方面的效率。