About FluidX3D
The story behind the fastest open-source GPU CFD simulator – and why we built this resource.
What Is FluidX3D?
FluidX3D is the fastest and most memory-efficient open-source computational fluid dynamics (CFD) solver available today. Built on the lattice Boltzmann method (LBM), it runs on virtually any GPU or CPU through OpenCL, with no vendor lock-in to NVIDIA CUDA. It can simulate turbulent flows, free surfaces, thermal convection, and particle dynamics at scales that were previously only possible with expensive commercial software.
Created by Dr. Moritz Lehmann under the ProjectPhysX banner, FluidX3D achieves performance benchmarks of up to 8,799 MLUPs/s on a single NVIDIA A100 and over 13,000 MLUPs/s on multi-GPU configurations. That translates to 100-200x faster than traditional finite-volume solvers running on equivalent hardware.
Development History
FluidX3D started as a research project exploring how GPU parallelism could transform fluid simulation performance. Dr. Moritz Lehmann, working at the intersection of physics and high-performance computing, built FluidX3D from scratch with a focus on memory efficiency and cross-platform GPU support.
Early Development
Dr. Lehmann begins developing a GPU-accelerated lattice Boltzmann solver using OpenCL to avoid CUDA vendor lock-in. The esoteric-pull streaming scheme is implemented, dramatically reducing memory usage to ~55-67 bytes per cell.
Open-Source Release
FluidX3D is released publicly on GitHub under ProjectPhysX. The repository includes full source code, build instructions for Windows/Linux/macOS, and example simulation setups for lid-driven cavities, flow around objects, and free-surface flows.
Multi-GPU and Advanced Features
Domain decomposition across multiple GPUs is added, allowing mixed-vendor setups (AMD + Intel + NVIDIA together). Temperature extensions, particle tracking, moving geometries, and VTK export for ParaView are introduced.
October 2024 – Version 3.5
The latest stable release brings improved real-time raytracing visualization, refined free-surface simulation with volume-of-fluid surface tension, and continued performance optimization. The project accumulates thousands of GitHub stars.
What Makes It Special
Several technical decisions set FluidX3D apart from every other open-source CFD solver:
- Memory efficiency: The esoteric-pull streaming scheme fits 19 million cells per gigabyte of VRAM in FP32/FP32 mode, compared to roughly 3 million for traditional LBM implementations. This means you can run billion-cell simulations on a single 8-GPU server.
- Cross-platform GPU support: OpenCL means FluidX3D runs on NVIDIA, AMD, and Intel GPUs equally well. No CUDA dependency, no vendor lock-in.
- Real-time visualization: Built-in GPU-accelerated raytracing lets you watch simulations unfold in real time with streamlines, velocity slices, and Q-criterion isosurfaces.
- FP16/FP32 mixed precision: Decoupled arithmetic and memory precision delivers higher throughput with minimal accuracy loss for most practical simulations.
- Single developer, remarkable output: The entire project is primarily the work of one person, Dr. Moritz Lehmann, which makes its performance and feature set even more impressive.
Who Uses FluidX3D
FluidX3D has found users across academic research, engineering prototyping, and hobbyist simulation communities. Researchers use it for turbulence studies and thermal convection modeling. Engineers use it for rapid prototyping of fluid flow problems that would take hours in commercial FVM solvers. Students use it to learn CFD without needing expensive ANSYS Fluent licenses.
The software is free for non-commercial use. Commercial licensing is available by contacting Dr. Lehmann directly.
The Developer
Dr. Moritz Lehmann operates under the ProjectPhysX name on GitHub. His background spans computational physics and GPU programming, with a particular focus on lattice Boltzmann methods and high-performance computing. Beyond FluidX3D, he has published research on GPU-accelerated scientific computing and contributed to the broader understanding of LBM optimization techniques.
For official communication, feature requests, or bug reports, visit the FluidX3D GitHub repository.
About This Website
fluidx3d.com is an independent, fan-made informational resource. We are not affiliated with, endorsed by, or officially associated with Dr. Moritz Lehmann or ProjectPhysX.
Our goal is straightforward: make it easier for people to find accurate information about FluidX3D, understand its capabilities, and access official download links. All download links on our site point to the official GitHub repository. We never host, modify, or redistribute software files.
We respect Dr. Lehmann’s work and encourage everyone to support FluidX3D by starring the repository, reporting issues through official channels, and respecting the software license.
Contact
Have questions or feedback about this website? Visit our Contact page. For official FluidX3D software support, please use the GitHub Issues page.