• This repo includes the source code for the SIGGRAPH Asia 2021 paper Fast Volume Rendering with Spatiotemporal Reservoir Resampling [Lin et al. 2021]. The project page of the paper can be found at https://dqlin.xyz/pubs/2021-sa-VOR/.
• The method is implemented as a render pass called "VolumetricReSTIR" (Source\RenderPasses\VolumetricReSTIR) in Falcor 4.2. There are also modifications in the original Falcor 4.2 code to support GVDB volumes. See README_Falcor.md for the original README file provided by Falcor.
• Some example scripts are provided to show how the method works in different scenes. "RunDemo.bat" contains a list of these scripts.
• Before running the scripts, you need to compile the program and download the scene files following the instruction below.

• Windows 10 version 1809 or newer
• Visual Studio 2019
• Microsoft Windows SDK version 1903 (10.0.18362.1) Or Newer (https://developer.microsoft.com/en-us/windows/downloads/sdk-archive)
• RTX 2060 or Higher

To reproduce the performance in the paper:

• Use RTX 3090 and GeForce Game Ready Driver Version 471.68
• Driver versions newer than 471.68 can cause significant slow down of our method with large VDB models (like the bunny cloud).

• Open Falcor.sln and Build Solution in configuration ReleaseD3D12

• execute RunDemo.bat (you can edit the script to select what you want to run)
• an example screenshot

• Download the example scenes (7.87 GB) here and extract the zip file inside Bin\x64\Release\Data
• You can also extract the zip file inside Source\RenderPasses\VolumetricReSTIR\Data. In this way, every time the project VolumetricReSTIR is built, the content will be pasted into the binary folder of your build configuration

• run GVDBConverter\gImportVDB.exe [Your VDB file].vdb [Number of Mip Levels]
• Example: GVDBConverter\gImportVDB.exe volumetric_bunny.vdb 4
• The converter will generate .vbx files for each mip map level and corresponding conservative grids (zero-density voxels are replaced by the average density of their neighbors). If the original VDB file contains temperature or velocity grids, they will also be converted into separate .vbx files.
• To compile the gImportVDB.exe, go to gvdb-voxel-src folder and use CMake. The source code is modified from https://github.com/NVIDIA/gvdb-voxels

• The denoiser requires CUDA (tested against 10.1/10.2, but higher versions should also be supported) and Optix 7.3. Make sure that you have those two SDKs in your computer if you want to use the Optix denoiser.
• Go to "Source\Externals.packman" and run mklink /J cuda [Your CUDA sdk installation directory] and mklink /J optix [Your Optix sdk installation directory] to create junctions named "cuda" and "optix"
• Example: mklink /J cuda "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v10.1" and mklink /J optix "C:\ProgramData\NVIDIA Corporation\OptiX SDK 7.3.0\include"
• Source\RenderPasses\VolumetricReSTIR\Scripts\run_plume_denoiser.py is an example script showing how to use optix denoiser on top of our render pass