Unity 6 / URP rendering playground for Nanite-style virtualized geometry, realtime GI, and a 24-hour sky.
基于 Unity 6 / URP 的 Nanite 风格虚拟几何、实时 GI 与 24 小时天空渲染实验。
项目验证帧中的 TOD 天空 / TOD sky from a project validation capture.
UnityNanite 是一个面向 Unity 6000.3.10f1 + URP 17.3.0 的图形实验项目。核心是把高面数模型离线拆分为 Cluster、Part 和可流送的 Page，在运行时通过 GPU 层级剔除与连续 LOD 选择可见几何，再用 VBuffer 完成材质解析。项目也包含独立的昼夜系统和仍在迭代的实时 GI。
当前主要面向 Windows x64 / Direct3D 12。它借鉴了虚拟几何的设计思路，不等同于 Unreal Engine 的 Nanite 实现。
- 离线几何烘焙： 借助 meshoptimizer 原生插件构建 Cluster 层级、连续 LOD、Part 和压缩 Page。
- GPU 驱动渲染： 视锥与 HZB 遮挡剔除、两阶段可见性选择、Page 常驻管理、VBuffer 材质解析和阴影路径。默认生产栅格模式为 HardwareOnly；Hybrid 路径保留用于实验。
- 实时 GI： 屏幕探针、世界空间缓存与 Nanite 几何适配，目前仍是实验模块。
- 24 小时 TOD： 可编辑的昼夜 Profile，以及动态天空、云、云影、雾和太阳/月亮 Lens Flare；该模块可以独立使用。
- 验证工具： Unity 编辑器诊断菜单、DX12 构建检查、RenderDoc 捕获与 GPU 时间分析脚本。
Nanite · 完整步骤
把 FBX/OBJ 放进 Assets/，打开 Nanite → Bake Nanite...，选择模型，设置输出目录与名称，并选 Static Base → Generate Static Base。将生成目录中的 Prefab/<名称>.prefab 拖入场景；在 Scene 视图的 Shading 下拉菜单选择 Nanite → Clusters / Triangles / Pages 预览。选中生成的 NaniteMesh 资源后，可从 Nanite → Diagnostics 运行 BVH/GPU 剔除检查。
GI · 完整步骤
在 PC_RPAsset 的 Deferred+ Renderer PC_Renderer 中启用 GIWorldRendererFeature，进入 Play Mode 查看 Game 视图。可读、不透明的普通 Mesh 会写入 GI 世界缓存；Nanite 由只读适配器读取已常驻 Page，再贡献几何，不会改写 Nanite 资源。运动物体加 Rigidbody 或 GITransformTracked。在 Feature 中启用 Debug，用 Surface / Source 检查覆盖，再比较 Diffuse Intensity 为 0 与 1 的画面。
TOD · 完整步骤
运行 Tools → Unity Nanite → TOD → Install Project Defaults，再用 GameObject → Unity Nanite → Create 24 Hour TOD Rig 在当前场景创建 Rig。选中 Rig，拖动 当前时间 预览；用 Window → Unity Nanite → 24 Hour TOD 编辑 Profile。最后运行 Tools → Unity Nanite → TOD → Validate Installation，并保存场景。
| 路径 | 内容 |
|---|---|
| Assets/Scripts/Nanite | 几何烘焙、运行时剔除、Page 管理、VBuffer 和编辑器工具 |
| Assets/GI | 实时 GI 的运行时 Pass、Compute Shader 与验证入口 |
| Assets/TOD | 独立的昼夜系统；见 TOD 使用说明 |
| Assets/Scenes | 示例场景 SampleScene |
| Assets/Sponza / Assets/Shaderball2 | 场景与模型资源 |
| Packages | 包清单及包含 Nanite 桥接修改的内嵌 URP |
| Native/API_CPP | meshoptimizer 的 C++ 插件封装与构建说明 |
| Tools | Nanite 验收、RenderDoc 捕获与分析脚本 |
| ProjectSettings | Unity 工程设置 |
- 用 Unity 6000.3.10f1 打开仓库根目录。等待 Package Manager 完成导入；项目使用仓库内的定制 URP 包。
- 在 Windows 上使用 Direct3D 12，打开
Assets/Scenes/SampleScene.unity。 - 在 Unity 菜单中选择 Nanite → Bake Nanite... 烘焙模型；
Assets/Plugins/x86_64/API_CPP.dll是随项目提供的 Windows 原生插件。需要重编译时参见 原生插件说明。 - 若要体验昼夜系统，参见 TOD 操作指南。在构建 Windows Player 前，可运行 Tools → Nanite → Validate DX12 Portability Contract。
这是图形研究工程，不保证其他平台、渲染 API 或 Unity 版本可直接运行。
- Unreal Engine Nanite 文档：虚拟几何的概念与设计参考。
- meshoptimizer：网格处理算法与原生插件依赖；见其 MIT 许可证。
- Unity URP 文档：URP、Renderer Feature 与 Render Graph 的接口参考。
- RenderDoc：图形帧捕获与 GPU 性能分析工具。
仓库目前没有统一的项目许可证；第三方代码与资源仍受各自许可证约束。
UnityNanite is a graphics experiment built with Unity 6000.3.10f1 and URP 17.3.0. It bakes high-poly meshes into clusters, parts, and streamable pages. At runtime, GPU hierarchy culling and continuous LOD select visible geometry, and a VBuffer resolves materials. The repository also includes an independent time-of-day system and an evolving realtime GI module.
The current target is Windows x64 with Direct3D 12. The project takes inspiration from virtualized geometry techniques; it is not an Unreal Engine Nanite port.
- Offline geometry baking: Builds a cluster hierarchy, continuous LOD, parts, and compressed pages using a native meshoptimizer wrapper.
- GPU-driven rendering: Frustum and HZB occlusion culling, two-stage visibility selection, page residency, VBuffer material resolve, and shadows. HardwareOnly is the production raster mode; Hybrid is experimental.
- Realtime GI: Screen probes, a world-space cache, and Nanite geometry integration. This module is still experimental.
- 24-hour time of day: Editable profiles, sky, clouds, cloud shadows, fog, and sun/moon lens flares. It can be used independently.
- Diagnostics: Unity editor validation menus, a DX12 build guard, and RenderDoc capture and GPU timing scripts.
Nanite · Full guide
Import an FBX/OBJ under Assets/, open Nanite → Bake Nanite..., select the model and an output folder, then choose Static Base → Generate Static Base. Drag the generated Prefab/<name>.prefab into the scene. Use the Scene view Shading → Nanite → Clusters / Triangles / Pages modes to inspect it. Select the generated NaniteMesh asset and run the BVH/GPU checks under Nanite → Diagnostics.
GI · Full guide
Enable GIWorldRendererFeature on the Deferred+ PC_Renderer used by PC_RPAsset, then enter Play Mode and inspect the Game view. Readable opaque ordinary meshes populate the GI world cache. The Nanite adapter reads resident pages without modifying Nanite resources and also contributes geometry. Add Rigidbody or GITransformTracked for rigid motion. Use Enable Debug → Surface / Source to inspect coverage, then compare Diffuse Intensity at 0 and 1.
TOD · Full guide
Run Tools → Unity Nanite → TOD → Install Project Defaults, then GameObject → Unity Nanite → Create 24 Hour TOD Rig in the target scene. Select the Rig and move 当前时间 (Current Time) to preview it. Edit profiles through Window → Unity Nanite → 24 Hour TOD. Run Tools → Unity Nanite → TOD → Validate Installation and save the scene.
| Path | Purpose |
|---|---|
| Assets/Scripts/Nanite | Baking, runtime culling, page management, VBuffer, and editor tools |
| Assets/GI | GI runtime passes, compute shaders, and validation entry points |
| Assets/TOD | Independent time-of-day module; see its guide |
| Assets/Scenes | SampleScene demo scene |
| Assets/Sponza / Assets/Shaderball2 | Scene and model assets |
| Packages | Package manifest and the embedded URP package with a Nanite bridge |
| Native/API_CPP | C++ meshoptimizer wrapper and build instructions |
| Tools | Nanite acceptance and RenderDoc analysis scripts |
| ProjectSettings | Unity project configuration |
- Open the repository root in Unity 6000.3.10f1 and allow Package Manager to import the embedded URP package.
- On Windows, select Direct3D 12 and open
Assets/Scenes/SampleScene.unity. - Use Nanite → Bake Nanite... to bake a mesh. The repository includes
Assets/Plugins/x86_64/API_CPP.dll; see the native plugin guide if you need to rebuild it. - Follow the TOD guide to try the sky system. Before building a Windows Player, run Tools → Nanite → Validate DX12 Portability Contract.
This is a graphics research project. Other platforms, graphics APIs, and Unity versions are not verified.
- Unreal Engine Nanite documentation — conceptual reference for virtualized geometry.
- meshoptimizer — mesh processing algorithms and native dependency, under its MIT license.
- Unity URP documentation — URP, Renderer Feature, and Render Graph APIs.
- RenderDoc — graphics capture and GPU analysis.
No repository-wide license is currently provided. Third-party code and assets retain their own license terms.