RTX Mega Geometry 0.9 (Beta)

· Change Log · Quick Start ·

Overview

RTX Mega Geometry (RTXMG) is a DX12 code sample that shows how to use NvAPI to quickly build ray-tracing acceleration structures for subdivision surfaces with structured clusters. It contains a reference HLSL path tracing demo app that can be used as a learning tool to begin integration with your own graphics engine.

Features

• Real-time adaptive sampling of Catmull-Clark limit surfaces
• Structured cluster tessellation and displacement mapping
• BVH build with NVAPI cluster template extensions for DXR
• Hierarchical Z-buffer for reducing tessellation rate of non-primary ray geometry
• DLSS Ray Reconstruction denoising

Requirements

• Windows 10
• NVIDIA RTX GPU (10 GB VRAM)
• GeForce Game Ready Driver 570 or newer
• DirectX 12 SDK with Shader Model 6.6 support (CMake fetches D3D12 Agility SDK automatically)
• DirectX Raytracing 1.1 API or higher
• CMake v3.31+
• Visual Studio 2019 or later with Windows 10 SDK version 10.0.20348.0 or later

Folder Structure

/bin	default CMake folder for binaries and compiled shaders
/build	default CMake folder for build files
/external	external submoduled libraries and SDKs, including osd_lite and donut
/assets	models, textures, scene files (git submodule)
/rtxmg	RTX Mega Geometry core

Build

At the moment, only Windows builds are supported.

1. Clone the repository with all submodules recursively:

   git clone --recurse-submodules https://github.com/NVIDIA-RTX/rtxmg.git

2. Use CMake to configure the build and generate the project files.

   cd rtxmg
   cmake CMakeLists.txt -B ./build
   

   Use -G "some tested VS version" if specific Visual Studio or other environment version required. Make sure the x64 platform is used.

3. Build the solution generated by CMake in the ./build/ folder.

   For example, if using Visual Studio, open the generated solution build/rtxmg.sln and build it.

4. Select and run the rtxmg_demo project. Binaries get built to the bin folder. Media assets are loaded from the assets folder.

User Interface

Once the application is running, most of the SDK features can be accessed via the UI window on the left hand side. The UI is self-documenting : hover the mouse over widgets to read tool-tips. See the Quick Start guide for more details.

Camera can be moved using W/S/A/D keys and rotated by dragging with the left mouse cursor. Holding the Alt key and left-click dragging will orbit the camera around the scene's center.

Command Line

• -mf loads a specific .scene.json or OBJ file; example: -mf programmer-art.scene.json
• -d to enable the graphics API debug layer or runtime, and the NVRHI validation layer.

Additional command line flags can be found by running with the -h flag.

Contact

RTX Mega Geometry is under active development. Please report any issues directly through GitHub issue tracker, and for any information, suggestions or general requests please feel free to contact us at [email protected]

Related RTX Mega Geometry Repositories

Vulkan

• vk_animated_clusters : VK_NV_cluster_acceleration_structure for animated content.
• vk_tessellated_clusters : adaptive triangle tessellation and displacement using VK_NV_cluster_acceleration_structure
• vk_lod_clusters : cluster-lod system and streaming using VK_NV_cluster_acceleration_structure
• vk_partitioned_tlas update the TLAS of large dynamic scenes with VK_NV_partitioned_acceleration_structure

Tools

• nv_cluster_builder spatial clustering algorithms for triangle meshes (C++ library)
• nv_cluster_lod_builder continuous level of detail (LOD) for triangle meshes (C++ library)

Citation

If you use RTX Mega Geometry in a research project leading to a publication, please cite the project.

BibTex:

@online{RTXMG,
   title   = {{{NVIDIA}}\textregistered{} {RTX Mega Geometry}},
   author  = {{NVIDIA}},
   year    = 2025,
   url     = {https://github.com/NVIDIA-RTX/rtxmg.git},
   urldate = {2025-02-06},
}

Known Issues

1. The RTXMG SDK does not currently support unstructured clusters or rasterization.

License

See LICENSE.txt

This project includes NVAPI software. All uses of NVAPI software are governed by the license terms specified here: https://github.com/NVIDIA/nvapi/blob/main/License.txt.