FluidX3D

The fastest and most memory efficient lattice Boltzmann CFD software, running on all GPUs and CPUs via OpenCL. Free for non-commercial use.

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Update History

• v1.0 (04.08.2022) changes (public release)
• public release
• v1.1 (29.09.2022) changes (GPU voxelization)
• added solid voxelization on GPU (slow algorithm)
• added tool to print current camera position (key G)
• minor bug fix (workaround for Intel iGPU driver bug with triangle rendering)
• v1.2 (24.10.2022) changes (force/torque computation)
• added functions to compute force/torque on objects
• added function to translate Mesh
• added Stokes drag validation setup
• v1.3 (10.11.2022) changes (minor bug fixes)
• added unit conversion functions for torque
• FORCE_FIELD and VOLUME_FORCE can now be used independently
• minor bug fix (workaround for AMD legacy driver bug with binary number literals)
• v1.4 (14.12.2022) changes (Linux graphics)
• complete rewrite of C++ graphics library to minimize API dependencies
• added interactive graphics mode on Linux with X11
• fixed streamline visualization bug in 2D
• v2.0 (09.01.2023) changes (multi-GPU upgrade)
• added (cross-vendor) multi-GPU support on a single node (PC/laptop/server)
• v2.1 (15.01.2023) changes (fast voxelization)
• made solid voxelization on GPU lightning fast (new algorithm, from minutes to milliseconds)
• v2.2 (20.01.2023) changes (velocity voxelization)
• added option to voxelize moving/rotating geometry on GPU, with automatic velocity initialization for each grid point based on center of rotation, linear velocity and rotational velocity
• cells that are converted from solid->fluid during re-voxelization now have their DDFs properly initialized
• added option to not auto-scale mesh during read_stl(...), with negative size parameter
• added kernel for solid boundary rendering with marching-cubes
• v2.3 (30.01.2023) changes (particles)
• added particles with immersed-boundary method (either passive or 2-way-coupled, only supported with single-GPU)
• minor optimization to GPU voxelization algorithm (workgroup threads outside mesh bounding-box return after ray-mesh intersections have been found)
• displayed GPU memory allocation size is now fully accurate
• fixed bug in write_line() function in src/utilities.hpp
• removed .exe file extension for Linux/macOS
• v2.4 (11.03.2023) changes (UI improvements)
• added a help menu with key H that shows keyboard/mouse controls, visualization settings and simulation stats
• improvements to keyboard/mouse control (+/- for zoom, mouseclick frees/locks cursor)
• added suggestion of largest possible grid resolution if resolution is set larger than memory allows
• minor optimizations in multi-GPU communication (insignificant performance difference)
• fixed bug in temperature equilibrium function for temperature extension
• fixed erroneous double literal for Intel iGPUs in skybox color functions
• fixed bug in make.sh where multi-GPU device IDs would not get forwarded to the executable
• minor bug fixes in graphics engine (free cursor not centered during rotation, labels in VR mode)
• fixed bug in LBM::voxelize_stl() size parameter standard initialization
• v2.5 (11.04.2023) changes (raytracing overhaul)
• implemented light absorption in fluid for raytracing graphics (no performance impact)
• improved raytracing framerate when camera is inside fluid
• fixed skybox pole flickering artifacts
• fixed bug where moving objects during re-voxelization would leave an erroneous trail of solid grid cells behind
• v2.6 (16.04.2023) changes (Intel Arc patch)
• patched OpenCL issues of Intel Arc GPUs: now VRAM allocations >4GB are possible and correct VRAM capacity is reported
• v2.7 (29.05.2023) changes (visualization upgrade)
• added slice visualization (key 2 / key 3 modes, then switch through slice modes with key T, move slice with keys Q/E)
• made flag wireframe / solid surface visualization kernels toggleable with key 1
• added surface pressure visualization (key 1 when FORCE_FIELD is enabled and lbm.calculate_force_on_boundaries(); is called)
• added binary .vtk export function for meshes with lbm.write_mesh_to_vtk(Mesh* mesh);
• added time_step_multiplicator for integrate_particles() function in PARTICLES extension
• made correction of wrong memory reporting on Intel Arc more robust
• fixed bug in write_file() template functions
• reverted back to separate cl::Context for each OpenCL device, as the shared Context otherwise would allocate extra VRAM on all other unused Nvidia GPUs
• removed Debug and x86 configurations from Visual Studio solution file (one less complication for compiling)
• fixed bug that particles could get too close to walls and get stuck, or leave the fluid phase (added boundary force)
• v2.8 (24.06.2023) changes (documentation + polish)
• finally added more documentation
• cleaned up all sample setups in setup.cpp for more beginner-friendliness, and added required extensions in defines.hpp as comments to all setups
• improved loading of composite .stl geometries, by adding an option to omit automatic mesh repositioning, added more functionality to Mesh struct in utilities.hpp
• added uint3 resolution(float3 box_aspect_ratio, uint memory) function to compute simulation box resolution based on box aspect ratio and VRAM occupation in MB
• added bool lbm.graphics.next_frame(...) function to export images for a specified video length in the main_setup compute loop
• added VIS_... macros to ease setting visualization modes in headless graphics mode in lbm.graphics.visualization_modes
• simulation box dimensions are now automatically made equally divisible by domains for multi-GPU simulations
• fixed Info/Warning/Error message formatting for loading files and made Info/Warning/Error message labels colored
• added Ahmed body setup as an example on how body forces and drag coefficient are computed
• added Cessna 172 and Bell 222 setups to showcase loading composite .stl geometries and revoxelization of moving parts
• added optional semi-transparent rendering mode (#define GRAPHICS_TRANSPARENCY 0.7f in defines.hpp)
• fixed flickering of streamline visualization in interactive graphics
• improved smooth positioning of streamlines in slice mode
• fixed bug where mass and massex in SURFACE extension were also allocated in CPU RAM (not required)
• fixed bug in Q-criterion rendering of halo data in multi-GPU mode, reduced gap width between domains
• removed shared memory optimization from mesh voxelization kernel, as it crashes on Nvidia GPUs with new GPU drivers and is incompatible with old OpenCL 1.0 GPUs
• fixed raytracing attenuation color when no surface is at the simulation box walls with periodic boundaries
• v2.9 (31.07.2023) changes (multithreading)
• added cross-platform parallel_for implementation in utilities.hpp using std::threads
• significantly (>4x) faster simulation startup with multithreaded geometry initialization and sanity checks
• faster calculate_force_on_object() and calculate_torque_on_object() functions with multithreading
• added total runtime and LBM runtime to lbm.write_status()
• fixed bug in voxelization ray direction for re-voxelizing rotating objects
• fixed bug in Mesh::get_bounding_box_size()
• fixed bug in print_message() function in utilities.hpp
• v2.10 (05.11.2023) changes (frustum culling)
• improved rasterization performance via frustum culling when only part of the simulation box is visible
• improved switching between centered/free camera mode
• refactored OpenCL rendering library
• unit conversion factors are now automatically printed in console when units.set_m_kg_s(...) is used
• faster startup time for FluidX3D benchmark
• miner bug fix in voxelize_mesh(...) kernel
• fixed bug in shading(...)
• replaced slow (in multithreading) std::rand() function with standard C99 LCG
• more robust correction of wrong VRAM capacity reporting on Intel Arc GPUs
• fixed some minor compiler warnings
• v2.11 (07.12.2023) changes (improved Linux graphics)
• interactive graphics on Linux are now in fullscreen mode too, fully matching Windows
• made CPU/GPU buffer initialization significantly faster with std::fill and enqueueFillBuffer (overall ~8% faster simulation startup)
• added operating system info to OpenCL device driver version printout
• fixed flickering with frustum culling at very small field of view
• fixed bug where rendered/exported frame was not updated when visualization_modes changed
• v2.12 (18.01.2024) changes (faster startup)
• ~3x faster source code compiling on Linux using multiple CPU cores if make is installed
• significantly faster simulation initialization (~40% single-GPU, ~15% multi-GPU)
• minor bug fix in Memory_Container::reset() function
• v2.13 (11.02.2024) changes (improved .vtk export)
• data in exported .vtk files is now automatically converted to SI units
• ~2x faster .vtk export with multithreading
• added unit conversion functions for TEMPERATURE extension
• fixed graphical artifacts with axis-aligned camera in raytracing
• fixed get_exe_path() for macOS
• fixed X11 multi-monitor issues on Linux
• workaround for Nvidia driver bug: enqueueFillBuffer is broken for large buffers on Nvidia GPUs
• fixed slow numeric drift issues caused by -cl-fast-relaxed-math
• fixed wrong Maximum Allocation Size reporting in LBM::write_status()
• fixed missing scaling of coordinates to SI units in LBM::write_mesh_to_vtk()
• v2.14 (03.03.2024) changes (visualization upgrade)
• coloring can now be switched between velocity/density/temperature with key Z
• uniform improved color palettes for velocity/density/temperature visualization
• color scale with automatic unit conversion can now be shown with key H
• slice mode for field visualization now draws fully filled-in slices instead of only lines for velocity vectors
• shading in VIS_FLAG_SURFACE and VIS_PHI_RASTERIZE modes is smoother now
• make.sh now automatically detects operating system and X11 support on Linux and only runs FluidX3D if last compilation was successful
• fixed compiler warnings on Android
• fixed make.sh failing on some systems due to nonstandard interpreter path
• fixed that make would not compile with multiple cores on some systems
• [v2.15](https://gith