Changelog

Jitter 2.13.0 (2026-10-22)

• Breaking Change: Removed the previous speculative contact system and replaced it with continuous collision detection (CCD), supporting both translation and rotation with iterative contact discovery. Use RigidBody.EnableCcd and the Ccd* settings; the old speculative contact API has been removed.
• Fixed angular NarrowPhase.Sweep missing collisions between separated start and end poses. Added a time-limited overload that distinguishes hits, misses, and searches that could not finish.
• Added a DynamicTree.SweepCast overload for shapes that translate and rotate.
• Improved ToString output for bodies, constraints, limits, and math types. Added numeric format and culture options for bodies, limits, and math types.
• Revised XML API documentation for clearer descriptions and usage guidance.

Jitter 2.12.2 (2026-10-22)

• Fixed a stack overflow that could occur during dynamic tree balancing, particularly in double precision.

Jitter 2.12.1 (2026-10-21)

• Improved contact point accuracy against flat surfaces, fixing artificial acceleration of rolling spheres.
• Fixed outdated contact normals and friction directions when contacting surfaces change orientation.
• Avoided unnecessary dynamic tree rearrangements during optimization of stationary scenes.

Jitter 2.12.0 (2026-10-19)

• Added AngularServo, TwistServo, LinearServo, and LinearAxisServo for driving target orientations, angles, and positions with torque or force limits.
• Added JointDrive to select a motor or servo when constructing hinge, prismatic, and universal joints. The existing hasMotor constructors remain available but are obsolete.
• Added DebugDrawSettings.PointRadius to control point marker size independently of constraint guides.
• Improved rolling stability by preserving the original contact in auxiliary manifolds with fewer than four points.

Jitter 2.11.0 (2026-10-18)

• Breaking Change: IDebugDrawer.DrawSegment and DrawTriangle now require a uint color packed as 0xRRGGBBAA. Custom drawers must implement both colored methods.
• Improved contact and constraint solver performance, especially in multithreaded scenes and for constraints attached to World.NullBody.
• Improved rolling stability with substeps by fixing contact impulses that could artificially accelerate rolling objects.
• Fixed angular velocity incorrectly influencing speculative contacts. Collision prediction and speculative response now consistently use linear motion.
• Added EllipticalConeLimit for different swing limits in two perpendicular directions, with optional inner limits and unrestricted twist.
• Expanded debug drawing for shapes, bodies, constraints, and joints, with clearer anchors, limits, axes, and motor directions.

Jitter 2.10.1 (2026-10-15)

• Added Constraint.Tag for attaching custom user data to constraints, matching RigidBody.Tag.

Jitter 2.10.0 (2026-10-11)

• Breaking Change: Added TimeStep with full-step and substep timing information. World step and substep callbacks and SoftBody.WorldOnPostStep now receive TimeStep; custom constraint solver callbacks and contact preparation now take in TimeStep instead of an inverse timestep.
• Breaking Change: Renamed the three BoxShape constructor parameters to sizeX, sizeY, and sizeZ. Update calls using named arguments.
• Breaking Change: ConvexPolytope now contains reusable managed storage, and its InitTetrahedron methods return a success flag. Added AddVertexDetailed for reporting expansion outcomes.
• Fixed substep scaling of motor force and torque limits and constraint softness, including soft-body springs. This changes simulation behavior when SubstepCount > 1.
• Added AngularMotor.MaximumTorque and deprecated its MaximumForce alias.
• Improved EPA robustness with filtered exact predicates and double-precision contact calculations, and improved GJK closest-point precision for small separations.
• Fixed TriangleShape ray casts reporting intersections behind the ray origin.
• Breaking Change: Body motion type changes no longer remove constraints or raise World.ConstraintRemoved. Constraints retain their enabled state, are suspended while neither connected body is dynamic, and resume when a dynamic body wakes. Use World.Remove(constraint) for permanent removal.
• Fixed moving kinematic bodies incorrectly falling asleep, including at very low speeds and with a zero deactivation time.
• Added DynamicTree.Update(proxy, dt) and fixed speculative broadphase bounds after velocity, impulse, and speculative contact setting changes, including before the first simulation step.
• Rebuilt dynamic tree collision pairs immediately when its filter changes, preserving the previous filter and pairs if the new filter throws.
• Fixed contact and island state when BeginCollide handlers remove bodies, shapes, or arbiters, including cancellation of pending contacts.
• Made RigidBody.AddShape roll back on registration or mass calculation failures, and tree proxy registration roll back when filtering throws.
• Fixed World.Clear leaving shapes attached to World.NullBody.
• Made SoftBody.Destroy safe after repeated calls, world clearing, or disposal. Added validation and bounding box updates for SoftBodyTriangle.Thickness.
• Fixed neighbor index overflow in large convex hulls and bounding box initialization for detached convex hull and point cloud shapes.
• Fixed inertia calculation for nested TransformedShape instances.
• Improved validation for removed bodies and constraints, invalid bodies passed to World.CreateConstraint, and unregistered dynamic tree proxies.
• Added debug assertions for invalid rigid body and constraint data access and invalid arbiter creation arguments.
• PartitionedSet enumeration now throws when the set is modified instead of silently skipping elements.

Jitter 2.9.0 (2026-10-03)

• Added world-space translation and rotation locks via RigidBody.AllowedMotion and MotionAxes, including planar motion presets.
• Breaking Change: Inertia APIs now use JSymmetricMatrix; RigidBodyData.InverseMass is replaced by InverseMassVector. Update custom shapes and constraints accordingly.
• Fixed constraint mass solves, angular singularities, and fixed and boundary limits.
• Fixed speculative contact bias and CCD impulse preservation.
• Fixed possible overflow in rotation quaternion calculation.
• Added TriangleEdgeCollisionFilter.FilterDynamicBodies to control edge filtering for dynamic triangle bodies (disabled by default).

Jitter 2.8.13 (2026-09-19)

• Improved recovery from invalid internal state when user-provided code throws exceptions.

Jitter 2.8.12 (2026-09-15)

• Added World.Trim to release excess internal storage after large scene changes.
• Fixed a multithreaded contact creation race that could create duplicate collision pairs.
• Fixed managed memory growth from arbiter pooling across worker threads.
• Improved validation and exception behavior for disposed worlds, removal calls, dynamic tree optimization, worker pools, and unmanaged memory helpers.
• Improved XML documentation for contact registration threading rules, arbiter lifetime, and public exception behavior.

Jitter 2.8.11 (2026-09-09)

• Added World.ConstraintRemoved for reacting to explicit and automatic constraint removal.
• Improved DynamicTree quality during regular updates with automatic incremental optimization and non-cost-increasing rotations.

Jitter 2.8.10 (2026-08-31)

• Added World.IsDisposed and IsValid properties for rigid bodies and constraints, allowing unavailable native state—including automatically removed constraints—to be detected safely.
• Ensured arbiters remain valid while EndCollide callbacks are running.
• Improved contact allocation and removal performance by eliminating unnecessary data movement between buffer partitions.

Jitter 2.8.9 (2026-07-24)

• Improved multithreading performance by reducing contention and cache-line ping-pong in reader-writer locks.

Jitter 2.8.8 (2026-05-24)

• Fixed triangle edge contact filtering by re-evaluating contacts after EPA.
• Rejected degenerate PointCloudShape volumes and zero-mass ConvexHullShape inputs during construction.
• Improved exception reporting for validation failures. Also added XML documentation for public exception behavior.

Jitter 2.8.7 (2026-05-17)

• Added World.ForceSleepIsland for immediately deactivating an island.
• Added argument validation for invalid shape dimensions, masses, constraint axes, and limits.
• Added debug-only checks for runtime state changes.
• Improved cleanup when simulation fails or gets interrupted.
• Fixed empty DynamicTree cost calculation.

Jitter 2.8.6 (2026-05-15)

• Added support for using multiple World instances from different host threads.
• Added World.IslandActivated and World.IslandDeactivated events for observing simulation island wake/sleep transitions.
• Fixed deterministic solver iteration handling in SolveMode.Deterministic.
• Fixed nested dynamic tree queries so callbacks may safely perform additional RayCast, SweepCast, and FindNearest queries.
• Fixed stale queued forces and torques when changing a body's MotionType.
• Breaking Change: Previously obsolete compatibility APIs now produce compile-time errors. Use the replacement APIs named in the obsolete messages.

Jitter 2.8.5 (2026-04-25)

• Improved CollisionManifold.

Jitter 2.8.4 (2026-04-19)

• Improved CollisionManifold generation by performing full clipping, producing better contact sets.
• Fixed indexed TriangleMesh adjacency generation for meshes with duplicated seam vertices.
• Added generic methods in ShapeHelper.
• Improved XML documentation throughout the codebase.

Jitter 2.8.3 (2026-04-13)

• Added SolveMode.Deterministic - an optional cross-platform deterministic solver mode.
• Fixed bugs in sleeping logic.
• Added PersistentContactManifold property.

Jitter 2.8.2 (2026-03-30)

• Added DynamicTree.SweepCast and DynamicTree.FindNearest - new tree queries combining broadphase pruning with exact narrowphase tests. SweepCast sweeps a shape through the tree; FindNearest finds the closest proxy by distance. Both include bounded variants and convenience overloads for common shapes.
• Added World.Stabilize - solves existing contacts and constraints at the velocity level without advancing body transforms. Useful for warm-starting a restored scene before resuming normal simulation.

Jitter 2.8.1 (2026-03-21)

• Fixed velocity setter bug in RigidBody - introduced in 2.8.0.
• Minor API improvements.

Jitter 2.8.0 (2026-03-19)

• Added RigidBody.AddImpulse methods for applying instantaneous impulses (linear and at a world-space position).
• Fixed corner case in wake-up logic: setting velocity to zero no longer unnecessarily activates sleeping bodies.
• Introduced ISink<T> interface and CollectionSink<T> adapter as a struct-friendly alternative to ICollection<T> on hot paths.
• Added ref TSink overloads for ShapeHelper.Tessellate and DynamicTree.Query.
• Extracted default constraint tuning values into named constants on the Constraint base class (DefaultLinearBias, DefaultLinearSoftness, DefaultAngularBias, etc.).
• Breaking Change: DynamicTree.Nodes changed from Node[] to ReadOnlySpan<Node>, exposing only the occupied portion of the internal array.
• Breaking Change: World.DebugTimings is now ReadOnlySpan<double> instead of double[].
• Renamed generic type parameters in NarrowPhase and CollisionManifold from TA/TB to Ta/Tb.

Jitter 2.7.9 (2026-02-14)

• Fixed distance calculation in SpringConstraint.
• Fixed register bug in UniversalJoint.
• Fixed ConeLimit.Limit property and added upper bound validation.
• Fixed inconsistent friction clamping between scalar and SIMD contact solver paths. Both paths now use the pre-update normal impulse for the friction cone.
• Fixed unnecessary wake-ups for sleeping bodies in contact with static bodies.
• Added basic debug draw methods to constraints.
• Added world ownership validation in World.Remove and World.CreateConstraint. Passing bodies, constraints, or arbiters from a different world now throws ArgumentException.
• Improved XML documentation throughout the codebase.

Jitter 2.7.8 (2026-01-18)

• Fixed degraded tree quality for large proxies in DynamicTree.
• Added JQuaternion.Lerp, JQuaternion.Slerp, JQuaternion.Dot, and JQuaternion.Inverse methods for quaternion interpolation and math.
• Added JTriangle.GetCenter, JTriangle.GetNormal, JTriangle.GetArea, JTriangle.GetBoundingBox, and JTriangle.ClosestPoint helper methods.
• Added JBoundingBox.Disjoint and JBoundingBox.Contains methods (also in TreeBox).
• Added World.GetArbiter(id0, id1) to retrieve existing arbiters without creating new ones.
• Improved XML documentation throughout the codebase.
• Fixed CalculateMassInertia in TransformedShape returning incorrect values.
• Fixed normalization bug in TriangleEdgeCollisionFilter.
• Fixed validation in SphereShape radius setter.
• Fixed a bug in speculative contact implementation.
• Improved TriangleMesh. Added option to build directly from vertices and indices.
• Added overloads for Span throughout the engine (in TriangleMesh, ShapeHelper, PointCloudShape, ConvexHullShape).

Jitter 2.7.7 (2026-01-08)

• Added vector.UnsafeAs<T> and JVector.UnsafeFrom<T>. Same for JQuaternion.
• Added world.PreSubStep and world.PostSubStep events.

Jitter 2.7.6 (2025-12-18)

• Removed World.Capacity. Number of entities in World no longer has to be specified in advance.
• Fixed a bug in TwistAngle.
• Added WeldJoint.
• Exposed more properties in ConeLimit.

Jitter 2.7.5 (2025-11-16)

• Improved cost heuristic for DynamicTree.

Jitter 2.7.4 (2025-10-29)

• Add MotionType property to RigidBody instances. Bodies might me Dynamic, Static or Kinematic. Static bodies with non-zero velocity are no longer supported, kinematic bodies must be used instead.
• The contact graph information is used to optimize the memory layout for contacts (ReorderContacts step). This makes the solver more cache friendly.
• Reduced overhead of CheckDeactivation step in the engine.

Jitter 2.7.3 (2025-10-19)

• Improved multi-threading performance.

Jitter 2.7.2 (2025-09-21)

• Reduced GC in DynamicTree.Optimize.
• Default to LocalRayCast if body is not set for RigidBodyShape.
• Added wakeup parameter to AddForce overloads for finer activation state control.
• Added generic ICloneableShape<T> interface for type-safe shape cloning.

Jitter 2.7.1 (2025-06-28)

• Added RigidBody.EnableGyroscopicForces to include gyroscopic forces.

Jitter 2.7.0 (2025-06-14)

• Dropped .NET7 support
• Added JQuaternion.ToAxisAngle method
• Renamed JBBox to JBoundingBoxand TreeBBox to TreeBox.
• Various smaller API changes.

Jitter 2.6.7 (2025-06-09)

• Introduced SIMD accelerated TreeBBox for DynamicTree.

Jitter 2.6.6 (2025-05-31)

• Implicit conversion for JVector and JQuaternion from tuples, e.g. cube.Position = (1, 2, 3);.
• Added PreStep and PostStep to World.Timings.
• Added NarrowPhase.Sweep overload which calculates time of impact (TOI) for rotating shapes.
• RegisterContact no longer requires a penetration and a speculative parameter.
• Bugfix: MathHelper.RotationQuaternion, fixed wrong/not normalized quaternion generation for large dt.
• Added an additional normal out-parameter to NarrowPhase.Distance.
• Renamed JVector.TransposedTransform(in JVector vector, in JQuaternion quat) to ConjugatedTransform.
• Added Anchor1 and Anchor2 properties to BallSocket.
• Bugfix: Skipping degenerate triangles in TriangleMesh now works correctly.

Jitter 2.6.5 (2025-05-21)

• Rigid bodies now activate on velocity or force changes.
• Removed FatTriangleShape.
• Renamed 'Active' to 'ActiveCount' and add span-based accessors in ReadOnlyPartitionedSet.
• Fixed bug in TriangleEdgeCollisionFilter.

Jitter 2.6.4 (2025-05-19)

• Breaking Change: Triangle winding order in TriangleMesh is now counter-clockwise (CCW) for front-facing triangles. If you're using TriangleMesh, swap the vertex order to maintain correct normal orientation.
• Added JTriangle.RayIntersect method.
• Renamed ConvexHullIntersection to CollisionManifold.
• Modified support function for BoxShape.

Jitter 2.6.3 (2025-05-17)

• Aligned rigid bodies (RigidBodyData) to a 64-byte boundary (reduce false sharing).
• Bugfix in speculative contacts.

Jitter 2.6.2 (2025-05-06)

• Use Generics in NarrowPhase.cs (avoid boxing for structs implementing the ISupportMappable interface).
• Added special code paths in Contact.cs for static bodies (avoid unnecessary cache line invalidation).
• Added PredictPosition, PredictOrientation and PredictPose to RigidBody.
• Added CreateFromAxisAngle and Normalize methods in JQuaternion.

Jitter 2.6.1 (2025-04-24)

• Bugfix in TriangleEdgeCollisionFilter for speculative contacts.

Jitter 2.6.0 (2025-04-24)

• Added SampleHull and MakeHull to ShapeHelper.
• Fixed hill climbing getting stuck for ConvexHullShapes.
• Added SIMD support for PointCloudShapes.
• Added option to ignore degenerated triangles in TriangleMesh.
• Made thickness parameter mandatory in FatTriangleShape.
• Added Fisher-Yates shuffle to DynamicTree.Optimize.
• Optimized TriangleEdgeCollisionFilter.

Jitter 2.5.9 (2025-04-17)

• Use CollideEpsilon 1e-5 in MPREPA.
• Fixed a bug in ShardedDictionary.

Jitter 2.5.8 (2025-04-16)

• Fixed DynamicTree.Optimize messing up collision pairs.
• Refactored SoftBody.cs
• Improved TriangleEdgeCollisionFilter.
• Further reduced GC.

Jitter 2.5.7 (2025-04-06)

• Fixed possible crash when dynamically making bodies static.
• Improved memory footprint and reduced GC.
• Added Logger as a replacement for Trace.

Jitter 2.5.6 (2025-03-08)

• Fixed concurrency bug in world.GetArbiter.

Jitter 2.5.5 (2025-03-02)

• Added implicit conversion operators for System.Numerics Vector3 and Quaternion.
• Replaced Trace.WriteLine with Trace.Information, Warning, Error.

Jitter 2.5.4 (2025-02-08)

• Renamed JAngle.Radiant to JAngle.Radian.
• Renamed namespace Jitter2.UnmanagedMemory to Jitter2.Unmanaged.
• Fixed body.AddShape(IEnumerable<RigidBodyShape> shapes) for one-time-use iterators.
• Smaller improvements in XML-documentation.

Jitter 2.5.3 (2025-01-12)

• DynamicTree, Optimize takes a delegate now.
• Fixed TriangleShape ray cast not returning a normalized normal.
• Removed the CollisionHelper class.
• Renamed ActiveList and UnmanagedActiveList to PartitionedSet and PartitionedBuffer, respectively.
• Various smaller improvements (ToString() overloads, IEquality<T> implementations, XML-documentation)

Jitter 2.5.2 (2025-01-08)

• Added enumeration method to DynamicTree and made PairHashSet internal.
• Breaking Change: Removed UseFullEPASolver option.
• Further improved simulation performance under high lock contention scenarios.

Jitter 2.5.1 (2024-12-31)

• Bugfix in PairHashSet.

Jitter 2.5.0 (2024-12-23)

• Better utilization of multi core systems.
• Bugfix in collision detection (possible NaN values).

Jitter 2.4.9 (2024-12-18)

• Huge improvements for the DynamicTree implementation.

Jitter 2.4.8 (2024-11-27)

• Add option to build in double precision mode.
• Made Constraint constructor public to allow for custom constraints.

Jitter 2.4.7 (2024-11-18)

• Breaking Change: Dropped .NET6 support, added .NET9.
• SIMD for contacts.
• Contact manifold overflow fix.
• Changed default damping.
• Improved auxiliary contact points.
• Minor API changes.

Jitter 2.4.6 (2024-10-28)

• Breaking Change: Jitter world is now constructed using World.Capacity.
• Breaking Change: World.RayCast moved to World.DynamicTree.RayCast.
• Breaking Change: Renamed NumberSubsteps to SubstepCount.
• Added split impulses. Breaking Change: SolverIterations property is now a tuple.
• Several smaller improvements in the API.

Jitter 2.4.5 (2024-10-07)

• Added new methods to NarrowPhase: Distance and Overlap.
• Breaking Change: Renamed NarrowPhase.SweepTest to NarrowPhase.Sweep.
• Breaking Change: Renamed NarrowPhase.GJKEPA to NarrowPhase.Collision.
• Made PointTest, Raycast and SweepTest to use new SimplexSolver and SimplexSolverAB implementations.
• Fixed normal in GJKEPA for separating case.

Jitter 2.4.4 (2024-09-14)

• Implemented fixes and workarounds for using Jitter with a debugger attached.

Jitter 2.4.3 (2024-08-31)

• Correct corner case beeing wrong in MPR collision detection due to typo (bug fix).
• FatTriangleShape level did not properly take transformations into account (bug fix).

Jitter 2.4.2 (2024-08-26)

• Added FatTriangleShape to give triangles thickness which can be useful for static triangle meshes.
• Removal from potential pairs in DynamicTree ignores filters from now on (bug fix).
• Use sweep tests for speculative contacts, vastly improving simulation quality in this scenario.
• Breaking Change: Redefinition of NarrowPhase.SweepTest results.
• Improved TriangleEdgeCollisionFilter.

Jitter 2.4.1 (2024-08-21)

• Improved TriangleEdgeCollisionFilter.
• Implemented analytical box and sphere ray casting.
• Made Restitution and Friction public in Contact.
• Improved DynamicTree interface.
• Added Debug.Asserts in ActiveList.
• Marked ArbiterKey as readonly.
• Added enumerator to PairHashSet.
• Changed ShapeHelper.MakeHull to take a generic of type ICollection.

Jitter 2.4.0 (2024-08-10)

• Improved TrimPotentialPairs logic.
• Optimized quaternion vector transformation.
• Extended functionality of ContactData.UsageMask.
• Breaking Change: Overhauled the shape system. Regular shapes (box, sphere, capsule, ...) now derive from RigidBodyShape. Some method signatures changed slightly, e.g. ray casting.
• Improved exceptions.
• Added ReferenceFrameAttribute.

Jitter 2.3.1 (2024-06-02)

• ReadOnly wrappers (ReadOnlyList, ReadOnlyHashset) are now structs.
• Shapes with very small dimensions might have close to zero or zero mass/inertia. Creating rigid bodies from them now throws an exception (use body.AddShape(shape, setMassInertia: false) to not use the shape's mass properties).
• Added BeginCollide and EndCollide events per body.

Jitter 2.3.0 (2024-05-20)

• Added RigidBody.RemoveShape overload to remove multiple shapes at once.
• Marked Rigid.ClearShapes deprecated.
• Breaking Change: Use JQuaternion for orientations. Sorry for the API break.

Jitter 2.2.1 (2024-04-29)

• Add optional activate parameter to world.AddShape.
• Add NarrowPhase.SweepTest.
• EPA collision detection: various improvements.
• Improve exit condition for RayCast and PointTest.
• Remove redundant ArgumentException for zero mass shapes.
• Handle zero time steps. Throw ArgumentException for negative time steps.
• Add joint base class to joint classes.

Jitter 2.2.0 (2024-01-02)

• Breaking Change: Renamed Raycast to RayCast.
• world.Remove(world.NullBody) does now remove all shapes, constraints and contacts associated with NullBody.
• world.AddShape(shape) respects the activation state of the associated rigid body. Most notable: performance improvement when directly adding TriangleShapes to world.NullBody for static geometry.
• Performance improvements for ConvexHullShape.
• Improved termination condition in GJKEPA collision detection.

Jitter 2.1.1 (2023-12-17)

• Fixed O(n^2) problem in TriangleMesh due to hash collisions.
• WorldBoundingBox of Shape is now updated even if no RigidBody is attached.

Jitter 2.1.0 (2023-12-10)

• Added debug drawing for rigid bodies (RigidBody.DebugDraw).
• Fixed a bug in CalculateMassInertia within TransformedShape.cs.
• Improved ray casting performance and introduced NarrowPhase.PointTest.
• Breaking Change: Inverted behavior of BroadPhaseCollisionFilter.
• Breaking Change: Inverted definition of damping factors in RigidBody.Damping (0 = no damping, 1 = immediate halt).
• Added RigidBody.SetMassInertia overload to enable setting the inverse inertia to zero.
• An exception is now thrown when a body's mass is set to zero.
• Fixed a bug in the friction handling in Contact.cs.

Jitter 2.0.1 (2023-10-28)

• Fixed a bug in contact initialization which affected soft body physics.

Jitter 2.0.0 (2023-10-22)

Initial stable Release.