Autostereoscopic display, despite decades of development, has not achieved extensive application, primarily due to the daunting challenge of 3D content creation for non-specialists. The emergence of Radiance Field as an innovative 3D representation has markedly revolutionized the domains of 3D reconstruction and generation. This technology greatly simplifies 3D content creation for common users, broadening the applicability of Light Field Displays (LFDs). However, the combination of these two fields remains largely unexplored. The standard paradigm to create optimal content for parallax-based light field displays demands rendering at least 45 slightly shifted views preferably at high resolution per frame, a substantial hurdle for real-time rendering. We introduce DirectL, a novel rendering paradigm for Radiance Fields on 3D displays. We thoroughly analyze the interweaved mapping of spatial rays to screen subpixels, precisely determine the light rays entering the human eye, and propose subpixel repurposing to significantly reduce the pixel count required for rendering. Tailored for the two predominant radiance fields--Neural Radiance Fields (NeRFs) and 3D Gaussian Splatting (3DGS), we propose corresponding optimized rendering pipelines that directly render the light field images instead of multi-view images. Extensive experiments across various displays and user study demonstrate that DirectL accelerates rendering by up to 40 times compared to the standard paradigm without sacrificing visual quality. Its rendering process-only modification allows seamless integration into subsequent radiance field tasks. Finally, we integrate DirectL into diverse applications, showcasing the stunning visual experiences and the synergy between LFDs and Radiance Fields, which unveils tremendous potential for commercialization applications. \href{direct-l.github.io}{\textbf{Project Homepage}

翻译：自动立体显示技术虽历经数十年发展，却因非专业用户难以进行三维内容创作的巨大挑战，至今未获广泛应用。辐射场作为一种创新的三维表示方法，显著革新了三维重建与生成领域。该技术极大降低了普通用户进行三维内容创作的门槛，拓宽了光场显示器的应用前景。然而，这两个领域的结合仍鲜有探索。为基于视差的光场显示器生成优质内容的标准范式，要求每帧至少渲染45个存在细微位移的视角（通常需高分辨率），这对实时渲染构成了重大障碍。本文提出DirectL，一种面向三维显示的辐射场新型渲染范式。我们深入分析了空间光线与屏幕子像素间的交织映射关系，精确确定了进入人眼的光线路径，并提出子像素重利用技术以显著降低渲染所需的像素数量。针对当前主流的两种辐射场表示——神经辐射场与三维高斯泼溅，我们分别提出了相应的优化渲染管线，可直接生成光场图像而非多视角图像。跨多种显示设备的广泛实验及用户研究表明，DirectL在保持视觉质量的前提下，相较标准范式可实现高达40倍的渲染加速。其仅修改渲染过程的特性，使其能无缝集成到后续辐射场任务中。最后，我们将DirectL集成到多种应用场景中，展示了光场显示器与辐射场结合所带来的惊艳视觉体验及其协同效应，揭示了巨大的商业化应用潜力。\href{direct-l.github.io}{\textbf{项目主页}}