Release history.

More reliable simulations and faster workflows

Changes

• Explore how a setup differs from the defaults with a step-by-step settings tour.
• Sharp-interface FLIP can use well-balanced gravity without liquid drifting from rest, including in compressible-gas cases.
• Run compressible-gas simulations during rotating-frame motion, with gas pressure staying consistent as gravity, rotation, acceleration, or the pivot changes.
• Run compressible gas with sharp interfaces and density projection in FLIP simulations.
• Sealed-ullage simulations can exchange mass with the liquid through evaporation and condensation, and results include ullage state and liquid-side interface heat.
• Tank meshes can seal a pressure domain without declaring every box face a wall, and sealed ullages retain pressure support.
• Closed tanks with baffles keep liquid from escaping through narrow wall gaps, while passive-gas simulations no longer classify wall support cells as gas.
• Sharp-interface FLIP stays stable around nearly closed cut faces instead of developing extreme velocities.
• Prescribed heat flux on curved walls is applied more consistently.
• Thermal simulations avoid spurious failures on already-converged solves, and failed solves provide clearer diagnostics.
• FLIP PBD simulations run faster.
• FIRM pressure solves and initialization run faster.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Steadier flows, clearer previews, faster solves

Changes

• FIRM pressure solves run faster, especially across repeated steps and multirate passes.
• FLIP adapts its time step to acceleration as well as fluid speed, and no longer imposes a default maximum time step; set dt_max if you want to cap it.
• Resumed runs keep probe measurements together in one file, and existing probe folders can be reused even if their ownership marker is missing.
• Copy buttons in the desktop app now place text on the system clipboard, so you can paste it into other applications.
• Draft previews stay more responsive in large particle scenes.
• Sealed PF-FLIP tanks can optionally model gas ullage with thermodynamics using the experimental flip.thermal.ullage setting.
• FIRM hydrostatic free surfaces stay more stable.
• FLIP free surfaces remain usable near colliders and in inlet or expression-defined scenes, without unsupported samples disrupting the surface.
• Resting free drops no longer pick up spurious whole-drop motion, and interface curvature remains available across the advected surface band.
• The viewer shows the body-surface color range beneath its field selector, and particles and free surfaces retain their selected-field colors where preview data is masked.
• Millimeter-scale bodies display smoother, more consistent surface shading when zoomed in.
• The setup viewer orients the scene using the gravity direction you authored, including z-up scenes.
• FLIP simulations reach the viewport during runs instead of stalling when the viewer publishes particle velocity.
• PF-FLIP transports heat through both liquid and gas phases.
• Sharp-interface PF-FLIP uses the density of the local particle mixture, improving liquid behavior where spray or entrained air is present.
• PF-FLIP now applies density projection by default when compatible; set c_div to keep it off, or enable density projection explicitly with mode on when appropriate.
• FLIP wall-load reports include liquid near the wall and account for wall acceleration, well-balanced gravity, and PF-FLIP.
• Thin baffles and folded sheets now block both flow and particle-to-grid transfers across their surfaces.
• Particle initialization now resolves samples in narrow wedges, small pockets, and corners where a thin baffle meets a tank wall.
• PCG pressure solves on sealed graphs can stop once the residual is within the uncertainty of the formed right-hand side, avoiding unnecessary work.
• Resolved liquid-gas simulations use dynamic pressure by default unless periodic gravity or a pressure outlet requires a hydrostatic reference.
• Resolved gas near sharp, unlabelled density changes behaves more reliably.
• Resolved multiphase pressure corrections better match the pressure gradient at interfaces, including near outlets, cut walls, contact lines, and passive-void surfaces.
• Fixed-count PISO now warns when under-relaxation leaves part of the pressure correction unapplied.
• Windows VTK frame renames recover more reliably when a file is temporarily unavailable.
• OBJ models with shared corners load without expanding every face corner into a separate vertex.
• FLIP particle volume can optionally expand or contract with temperature using the experimental flip.thermal.volume_expansion setting, while particle mass stays fixed.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Sharper wetting and surface tension, more accurate walls, and steadier moving bodies

Changes

• FLIP contact angles now default to a new automatic choice that uses the sharp wall-distance closure wherever the scene supports it and the previous force model otherwise; the choice and its reason are logged at startup.
• The sharp FLIP contact-angle closure now supports dynamic contact angles, including slip length, advancing and receding line friction, and hysteresis smoothing, and measures the angle against a smooth wall normal so faceted container meshes no longer cause drift.
• FLIP free surfaces now keep a particle level set, so still drops and resting liquids stay calmer under surface tension and the surface survives restarts.
• FLIP surface tension can now run at timesteps above the capillary limit on free surfaces by filtering the interface curvature; steps above that limit are rejected for scenes with bodies or contact angles, where they are not stable.
• FLIP viscous flow along no-slip walls no longer loses momentum to pressure-projection slip, which removes a timestep-dependent flow deficit in pressure-driven channels and pumps, for Newtonian and non-Newtonian fluids.
• FLIP Newtonian viscosity now uses the wall-aware cut-cell strain, and the wall shear stress output is now a local traction suitable for wall shear and oscillatory shear maps.
• FLIP geometric multigrid pressure solving is now a production option, and the automatic choice continues to select it on large grids.
• FLIP viscous simulations near walls are more robust, including near-tie wall samples and steps after the density projection moves particles.
• FVM moving-body cut cells now merge in groups, so clusters of thin slivers no longer stay unmerged or form stretched cells; any cells left unmerged are reported at startup.
• FVM moving-body drag is less noisy and no longer biased low, because newly cut cells now take full wall friction immediately.
• FVM rotating reference frames are now listed as a supported capability.
• FVM multigrid pressure solving now works on periodic domains instead of falling back to a much slower solver.
• FVM sealed pressure solves around static bodies, cut-face advection, wall loads, and two-phase interface pressure are more accurate.
• FVM moving-body scenes handle sampled cut cells more robustly and limit each step so a body moves at most half a cell between cut-cell updates.
• GPU initialization keeps scene geometry watertight under single-precision rounding.
• Vulkan FLIP viscous simulations no longer produce rare nondeterministic wall-strain errors on some drivers.
• Held cubic keyframes now start and stop at rest, so prescribed motion has no velocity jump at its first and last keys.
• Saving a scene now preserves prescribed rotation motion.
• FVM edge cases no longer access invalid GPU memory.
• The setup option fvm.mesh.cutcellagerampsteps has been removed; delete it from existing projects. Two held keyframes now ease in and out instead of moving linearly.

Breaking changes: existing projects or workflows may need changes before use.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Smoother animation and faster fluid simulations

Changes

• Looping animation timelines now join smoothly when their endpoints match, and motion channels can interpolate file-driven values and rotation speed.
• Cubic keyframes without authored tangents now move smoothly without overshooting, including rotation keyframes.
• The animation editor now shows the slopes used by cubic keyframes.
• Long animation timelines evaluate faster, and CSV timelines now use cubic interpolation by default.
• FVM mesh builds no longer fail on large grids that exceed a device's per-dispatch limit.
• Thin cut-cell slivers now initialize correctly, and seed initialization runs faster for fully filled moving-body scenes.
• FVM connected-component processing runs faster on large grids.
• FVM pressure solves run faster, with multigrid reaching deeper levels and a practical default stopping tolerance.
• Pressure solves with roundoff-sized residuals no longer stall during reliable restarts.
• FVM pressure and component calculations on Vulkan no longer lose small contributions during reductions.
• Pressure solvers for fully sealed domains now handle the arbitrary pressure offset consistently, including multigrid PCG.
• FVM multigrid pressure solving now works on two-dimensional and odd-sized grids.
• FLIP liquid inlets no longer push liquid back into a full tank during density projection.
• FLIP domain walls now extend past outlets while particles remain in the simulation.
• FVM cut-cell volumes are now integrated exactly, and moving-body projects must provide paired cut faces.
• You can choose the host-based topology-mask sampler with fvm.mesh.topologymaskbackend; GPU sampling remains the default.
• Experimental time-consistent Rhie-Chow interpolation is available for PISO face velocities, making steady-state results less dependent on the time step.
• FLIP scenes with six-degree-of-freedom bodies can now use geometric-multigrid PCG pressure solving.
• Passive-gas two-phase FLIP scenes can now use multigrid pressure solving, including automatic selection on larger grids.
• FLIP pressure solves now use a time-step-consistent divergence-rate stop by default, with an optional absolute divergence target; set flip.pressure.pcg.divergenceratetolerance to 0 to retain residual-only stopping.

Breaking changes: existing projects or workflows may need changes before use.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

More fluid models, tracers, and controls

Changes

• Create passive tracers in Probes, follow their live paths, and get tracer results from FLIP and FVM, including when implicit viscosity is off.
• Choose additional non-Newtonian fluid models, including regularized Herschel-Bulkley, Giesekus, and linear PTT.
• Inspect rheology convergence and timestep-retry diagnostics in simulation results and the info panel.
• Set temperature-dependent viscosity and shear-rate laws, with local-viscosity dynamic wetting.
• Inspect wall shear stress and accumulated TAWSS and OSI histories in simulation results.
• Color scene bodies by pressure or wall shear stress.
• Opt to halve the timestep and retry numerically failed steps in FLIP and FVM.
• Restart simulations with prescribed moving bodies.
• Run rheology simulations with prescribed deforming walls in FLIP and FVM.
• Run split-PLIC simulations with surface tension on resolved immersed geometry, rotating domains, and calm relaxation zones.
• Choose Auto, 1x, or 2x free-surface detail and use consistent quality for paused frames and exports.
• Run unattended command-line sessions and capture screenshots or VTK frames at intervals.

Migrating existing setups

• FLIP setups that still contain these removed settings are rejected; delete them: flip.impulse, flip.particles.reseeding, flip.advection.graphdeformation, flip.multiphase.igfm, flip.multiphase.massweightedcombine, flip.multiphase.advectcombined, flip.multiphase.velocitybandblend, flip.densityprojection.acknowledgeresearch and flip.surfacetension.wallcontactcurvaturemineffectivesamples.
• The FLIP variant "impulse_gfm" is no longer available; choose another FLIP variant.
• FLIP pressure: flip.pressure.pcg.preconditioner accepts auto, jacobipolynomial, tileblocksgs and the new geometricmultigrid. flip.pressure.multigrid and flip.pressure.pcg.additivecoarseorder are removed, and FLIP no longer accepts the jacobi, multigrid or mg_pcg pressure methods. Move a top-level pressure.multigrid section to fvm.pressure.multigrid.
• FLIP runs saved by 0.2.6 cannot be resumed; start them again. FLIP CSV results no longer have graph_deformation columns.
• FVM with immersed bodies now uses exact cut geometry by default where it applies. If your bodies are moved through the API after initialization instead of by a declared motion, set mesh.cutgeometrymode to "sampled".
• FVM resolved-gas setups on regular geometry that use fvm.multiphase.momentumtransport "velocity", or fvm.predictor.momentumtheta other than 1, now stop at initialization; set fvm.multiphase.alpha_transport to "mhric" to keep the previous behaviour.

Breaking changes: existing projects or workflows may need changes before use.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

More reliable flows and resumable runs

Changes

• Desktop runs can resume after reopening a document, and CLI runs can use setup-defined checkpoints; Restart still begins at time zero.
• Compatible PF-FLIP setups with surface tension now use sharp interfaces and carried curvature by default, with particle advection selected automatically.
• PF-FLIP interface motion is no longer damped by a PIC band by default, while explicitly configured band widths remain honored.
• Free surfaces no longer act like unintended viscous walls, including when boundary faces have no sampled velocity; PF-FLIP viscosity also includes both phases when their kinematic viscosities match.
• Flows between symmetry planes can slide tangentially instead of sticking to those boundaries.
• Fluid can move through gaps only one cell wide between walls.
• FLIP flows with particles moving one or two cells per step now preserve their motion more faithfully.
• Capillary flows near walls and contact lines no longer pick up spurious curvature effects.
• You can choose an experimental wall-energy contact-angle method for surface-tension simulations.
• Closed-tank PF-FLIP simulations can optionally model compressible air with an experimental option that is off by default.
• CLI setup validation now checks phase-model compatibility against the selected solver, avoiding false rejections from settings for other solvers.
• You can open a support email from the native application’s menu or About window.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

More reliable flows and CFD tooling

Changes

• Violent FLIP sloshing is less likely to be overdamped when particles travel multiple cells in a step.
• Coupled moving-wall simulations avoid pressure spikes from extremely short leftover substeps.
• Setup validation warns when positive phase viscosity will not be applied in FLIP or FIRM.
• FVM setup validation catches attempts to ramp gravity during both warmup and the simulation, preventing an unintended second ramp.
• FIRM preserves slow particle motion instead of freezing or biasing displacements toward zero.
• FLIP and FIRM mesh-inlet births now start on the receiving side of the cap, preventing trapped particles and spurious air at submerged FLIP inlets.
• Planar mesh inlets keep still water at rest, and FLIP divergence checks and projection solves behave better around split inlet cells.
• FVM PLIC now handles multiple separated static bodies and rigidly moving closed meshes, with automatic exact-cut selection when setup checks allow it.
• Windows and Linux desktop releases include an Agent Pack and CLI/MCP tools for setup validation and task-based CFD runs.
• Linux users can run a packaged FLIP dam-break against an elastic obstacle with the included CalculiX and preCICE tools.
• Two-phase PF-FLIP simulations can use volume correction to limit liquid-volume drift during expansion.
• PF-FLIP can derive its reference density from particle packing, adapting when particle count or kernel radius changes.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• FVM free-surface transport now handles moving and cut cells more consistently, including pressure and wall loads.
• Pressure outlets now support a hydrostatic reference level, helping preserve still water under gravity.
• Hybrid FLIP/APIC transfers now retain affine motion across steps, including near domain walls and immersed colliders.
• FLIP free-surface recording now handles surface velocities near curved walls more reliably.
• FLIP simulations can initialize faster by compiling only the transfer samplers used by the run.
• Harmonic axis and direction fields now retain entered values when applied and reloaded, with blank components treated as zero.
• Simulation initialization now explains that the device is being optimized and that later runs start faster.
• Preview priority now affects the balance between rendering and solving during idle playback.
• FVM now flags unsupported wall-pressure boundary conditions when using exact geometry.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• Single-liquid FLIP now enables the carried-phi level set by default in supported setups and can initialize it from expression and triangle-mesh interfaces.
• Passive-void free surfaces in FVM now move at the liquid's speed.
• FLIP contact-angle wetting now works on cut and curved mesh walls and avoids wall-induced bias in two-phase flows when an angle is set.
• FVM exact-geometry mode now supports static closed triangle meshes as obstacles or inverted containers.
• FVM now automatically selects split PLIC alpha transport when the simulation setup supports it, while retaining MHRIC for other setups.
• FVM initialization now handles cut-volume samples that fall on oblique walls or interfaces.
• FLIP more reliably preserves solid tank walls when multiple colliders are nearby.
• Carried-phi FLIP now handles initial interfaces along walls more consistently, improving still-fluid behavior in tanks.
• FLIP pressure and density-projection solves wait on the GPU less often per step, with unchanged results.

Breaking changes: existing projects or workflows may need changes before use.

• flip.interface.level_set.carried_phi_level_set is replaced by flip.interface.level_set.carried_phi_mode (auto, on or off); setups that use the old key are rejected with a pointer to the new one. auto, the default, now uses the carried-phi level set for single-liquid FLIP. Set off to keep the previous particle-splat level set, including when restoring checkpoints written with it.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• Scene simulation previews now start automatically after loading, use the Balanced setting, and show cached time ranges in the scrubber.
• Scene drafts now account for simulation cost when choosing their size, condition particles before projection, and can resume after releasing a running simulation.
• FLIP now uses least-squares interface curvature by default and can automatically enable density projection on supported desktop backends.
• FLIP density projection now handles recoverable rejected candidates without aborting the simulation.
• FLIP wall handling and contact-line damping have been corrected for particle movement and viscosity boundaries.
• FVM now preserves liquid volume and co-moving flow more consistently across moving-boundary recuts.
• FVM now warns when a moving body is used without cell pairing, and rejects gas-interface damping with the consistent corrector.

Breaking changes: existing projects or workflows may need changes before use.

• FLIP: flip.density_projection.enabled is no longer accepted. Use flip.density_projection.mode instead ("on" replaces enabled: true, "off" replaces enabled: false). Scenes without an explicit setting now use density projection where supported. A checkpoint saved without density projection can be resumed only with mode: "off" if the scene would now enable it automatically.
• FVM: setups that set fvm.multiphase.gas_interface_alpha_u below 1 with the default consistent corrector no longer load. Remove the field, or set fvm.multiphase.corrector to "legacy" to keep the previous damping.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• Release packages now include curated setup examples that you can open from the desktop app’s Open dialog.
• Viewer speed and pressure color scales now account for body rotation and surface motion, and are seeded from physical scales so developing flows remain visible.
• FIRM defaults to improved wall projection and automatic density projection, and supports density projection with the separation constraint.
• FLIP fills enclosed air cells in concave wall corners, keeps particles inside curved containers, and supports positional repair with multiple disjoint containers.
• FVM defaults to conservative momentum transport for resolved MHRIC and enables balanced surface tension by default.
• FLIP, FIRM, and FVM support temperature transport with Boussinesq buoyancy when thermal transport is enabled.
• The native viewer lets you select temperature as a displayed field and reports temperature in kelvins.

Breaking changes: existing projects or workflows may need changes before use. The changed FIRM and FVM defaults can change results for existing projects, so re-run and compare important cases before relying on them.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• Includes feature changes.
• Includes bug fixes.
• Includes performance-related implementation changes; no speedup is claimed.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• FLIP now supports planar mesh inlets with density projection, including split-cell flow and free-surface boundaries.
• FLIP supports planar disposal outlets with IDP.
• The liquid level set now continues into walls by default, improving still-water behavior in closed curved containers while keeping extracted surfaces clamped to the collider.
• Prescribed body rotations now use the configured reference rotation center.
• Density projection and PBD now handle particle corrections near curved walls without rejecting otherwise admissible positions.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.

Changes

• Initial alpha release of Prelimina.

Requirements and limitations

These binaries are unsigned. A Vulkan-capable GPU and vendor driver are required. CUDA and macOS packages are not included. Back up projects and keep them outside the installation directory.