### [IMPORTANT] Obi 7 is a major update. If you're updating from an older version, it will require you to redo the setup most of your existing Obi-related functionality. It is recommended to use Obi 7 on new projects only, or if you must update an existing one, plan accordingly and set aside some time to perform the update.

# Change Log

All notable changes to “Obi - Advanced fluids for Unity” will be documented in this file.

## [7.1]

### Added

- Added support for URP's RenderGraph API to transparent fluid rendering.

- Solvers can now optionally enforce boundary limits, so that particles can't go outside those limits. This is often more convenient than manually placing invisible colliders for the same purpose.

- Better foam/diffuse particle rendering. It now uses an approximate volumetric lighting mode, supporting shadow receiving/casting in URP.

- Added collider collision detection for foam/diffuse particles (Compute backend only).

- Added barolinic vorticity, allowing for more realistic gas simulation.

- ObiForceZones now have a "color" parameter, that can be used to change the color of particles entering the zone.

### Changed

- Better vorticity model, using micropolar formulation.

- Improved performance for large amounts of static colliders: they're not processed at all during ObiSolver.Update().

- Particle lifetimes are now managed by the solver backend, instead of the ObiEmitter component. This results in large performance savings when dealing with many particles, specially in the Compute backend.

## Fixed

- Null reference exception when using a ObiFluidSurfaceMesher without a fluid rendering pass.

## [7.0.5]

## Fixed

- Bug that caused fluid render passes to dispose the fluid material when still in use by other renderers.

- InvalidOperationException in Burst backend when having simulateWhenInvisible = false and solver not seen by any camera.

- Issue that caused foam to be generated for newly spawned particles even if it shouldn't.

## [7.0.4]

### Added

- Emitters now have a "Inherit velocity" property that allows fluid to inherit a percentage of the emitter's velocity.

### Fixed

- Bug that caused inactive particles to still be rendered by ObiInstancedParticleRenderer.

- Compute backend bug that caused foam particles to stop being updated when the amount of fluid particles in the solver is zero.

## [7.0.3]

### Added

- Object layer support for all renderers.

- New "Synchronous Fixed" solver synchronization mode, similar to Obi 6, offers tighter integration with rigidbody physics.

## [7.0.2]

### Fixed

- Solvers not placed at the scene origin would result in actors having incorrect motion blur in HDRP.

- Fixed issue when disabling all solvers and colliders simultaneously: ipon re-enabling them, the colliders would be ignored.

## [7.0.1]

### Added

- Render layer mask support to fluid renderers and particle renderers.

### Fixed

- Having a ObiParticleRenderer with no material applied resulted in a exception in builds due GetInstanceID() returning 0 in editor but raising a nullref exception in the build.

## [7.0]

### Added

- Compute shader based GPU solver backend.

- New unified viscosity/vorticity model, allows for larger viscosity values as well ass buckling/coiling effects.

- New polarity based surface tension model, allows for fluids of different polarities to repel each other.

- New fluid rendering system based on isosurface meshing.

- Fluid render passes, that allow to control which emitters get rendered using the same set of fluid render properties.

- More efficient solver update cycle, that also removes the need to have ObiUpdater components.

### Changed

- Rendering system is now fully multithreaded, integrated with the solver backend.

### Removed

- Native library based 'Oni' solver backend.

- ObiUpdater and all derived classes have been removed.

Obi Fluid