diff --git a/src/Box2D.NET.Samples/Graphics/Draws.cs b/src/Box2D.NET.Samples/Graphics/Draws.cs
index 7d1983da..d53c6367 100644
--- a/src/Box2D.NET.Samples/Graphics/Draws.cs
+++ b/src/Box2D.NET.Samples/Graphics/Draws.cs
@@ -63,7 +63,7 @@ public static void DrawSolidPolygon(Draw draw, in B2Transform transform, ReadOnl
         AddPolygon(ref draw.polygons, transform, vertices, vertexCount, radius, color);
     }
 
-    public static void DrawTransform(Draw draw, B2Transform transform, float scale)
+    public static void DrawTransform(Draw draw, in B2Transform transform, float scale)
     {
         B2Vec2 p1 = transform.p;
 
@@ -103,9 +103,9 @@ public static void DrawCircle(Draw draw, B2Vec2 center, float radius, B2HexColor
         AddCircle(ref draw.hollowCircles, center, radius, color);
     }
 
-    public static void DrawSolidCircle(Draw draw, B2Transform transform, float radius, B2HexColor color)
+    public static void DrawSolidCircle(Draw draw, in B2Transform transform, float radius, B2HexColor color)
     {
-        AddSolidCircle(ref draw.circles, ref transform, radius, color);
+        AddSolidCircle(ref draw.circles, transform, radius, color);
     }
 
     public static void DrawSolidCapsule(Draw draw, B2Vec2 p1, B2Vec2 p2, float radius, B2HexColor color)
diff --git a/src/Box2D.NET.Samples/Graphics/SolidCircles.cs b/src/Box2D.NET.Samples/Graphics/SolidCircles.cs
index 89025616..fb2f536f 100644
--- a/src/Box2D.NET.Samples/Graphics/SolidCircles.cs
+++ b/src/Box2D.NET.Samples/Graphics/SolidCircles.cs
@@ -96,7 +96,7 @@ public static void DestroySolidCircles(GL gl, ref SolidCircleRender render)
         }
     }
 
-    public static void AddSolidCircle(ref SolidCircleRender render, ref B2Transform transform, float radius, B2HexColor color)
+    public static void AddSolidCircle(ref SolidCircleRender render, in B2Transform transform, float radius, B2HexColor color)
     {
         RGBA8 rgba = RGBA8.MakeRGBA8(color, 1.0f);
         render.circles.Add(new SolidCircleData(transform, radius, rgba));
diff --git a/src/Box2D.NET.Samples/Primitives/CapsuleData.cs b/src/Box2D.NET.Samples/Primitives/CapsuleData.cs
index a54a9c62..53d43e4f 100644
--- a/src/Box2D.NET.Samples/Primitives/CapsuleData.cs
+++ b/src/Box2D.NET.Samples/Primitives/CapsuleData.cs
@@ -11,7 +11,7 @@ public struct CapsuleData
     public float length;
     public RGBA8 rgba;
 
-    public CapsuleData(B2Transform transform, float radius, float length, RGBA8 rgba)
+    public CapsuleData(in B2Transform transform, float radius, float length, RGBA8 rgba)
     {
         this.transform = transform;
         this.radius = radius;
diff --git a/src/Box2D.NET.Samples/Primitives/SolidCircleData.cs b/src/Box2D.NET.Samples/Primitives/SolidCircleData.cs
index f17d64e5..b05dcf6e 100644
--- a/src/Box2D.NET.Samples/Primitives/SolidCircleData.cs
+++ b/src/Box2D.NET.Samples/Primitives/SolidCircleData.cs
@@ -10,7 +10,7 @@ public struct SolidCircleData
     public float radius;
     public RGBA8 rgba;
 
-    public SolidCircleData(B2Transform transform, float radius, RGBA8 rgba)
+    public SolidCircleData(in B2Transform transform, float radius, RGBA8 rgba)
     {
         this.transform = transform;
         this.radius = radius;
diff --git a/src/Box2D.NET.Samples/Samples/Collisions/ShapeCast.cs b/src/Box2D.NET.Samples/Samples/Collisions/ShapeCast.cs
index 0c910bef..379cc1b3 100644
--- a/src/Box2D.NET.Samples/Samples/Collisions/ShapeCast.cs
+++ b/src/Box2D.NET.Samples/Samples/Collisions/ShapeCast.cs
@@ -189,7 +189,7 @@ private B2ShapeProxy MakeProxy(ShapeType type, float radius)
         return proxy;
     }
 
-    private void DrawShape(ShapeType type, B2Transform transform, float radius, B2HexColor color)
+    private void DrawShape(ShapeType type, in B2Transform transform, float radius, B2HexColor color)
     {
         switch (type)
         {
diff --git a/src/Box2D.NET.Samples/Samples/Collisions/ShapeDistance.cs b/src/Box2D.NET.Samples/Samples/Collisions/ShapeDistance.cs
index feb9ccc7..c80e0df8 100644
--- a/src/Box2D.NET.Samples/Samples/Collisions/ShapeDistance.cs
+++ b/src/Box2D.NET.Samples/Samples/Collisions/ShapeDistance.cs
@@ -164,7 +164,7 @@ B2ShapeProxy MakeProxy(ShapeType type, float radius)
         return proxy;
     }
 
-    void DrawShape(ShapeType type, ref B2Transform transform, float radius, B2HexColor color)
+    void DrawShape(ShapeType type, in B2Transform transform, float radius, B2HexColor color)
     {
         switch (type)
         {
@@ -389,8 +389,8 @@ public override void Draw()
         base.Draw();
 
         var empty = b2Transform_identity;
-        DrawShape(m_typeA, ref empty, m_radiusA, B2HexColor.b2_colorCyan);
-        DrawShape(m_typeB, ref m_transform, m_radiusB, B2HexColor.b2_colorBisque);
+        DrawShape(m_typeA, empty, m_radiusA, B2HexColor.b2_colorCyan);
+        DrawShape(m_typeB, m_transform, m_radiusB, B2HexColor.b2_colorBisque);
 
         if (m_drawSimplex)
         {
diff --git a/src/Box2D.NET.Samples/Samples/Issues/ShapeCastChain.cs b/src/Box2D.NET.Samples/Samples/Issues/ShapeCastChain.cs
index 7ab5151d..0d6d8996 100644
--- a/src/Box2D.NET.Samples/Samples/Issues/ShapeCastChain.cs
+++ b/src/Box2D.NET.Samples/Samples/Issues/ShapeCastChain.cs
@@ -216,7 +216,7 @@ private bool ShapeCastSingle(ref PhysicsHitQueryResult2D outResult, B2Vec2 start
             start,
             b2MakeRot(rotation)
         );
-        B2ShapeProxy transformedShape = TransformShapeProxy(ref transform, ref shape);
+        B2ShapeProxy transformedShape = TransformShapeProxy(transform, ref shape);
 
         B2Vec2 translation = new B2Vec2(end.X - start.X, end.Y - start.Y);
         B2QueryFilter filter = new B2QueryFilter(0x1, 0x1);
@@ -252,7 +252,7 @@ private static float b2CastResult_Closest(in B2ShapeId shapeId, B2Vec2 point, B2
         return fraction;
     }
 
-    private static B2ShapeProxy TransformShapeProxy(ref B2Transform t, ref B2ShapeProxy proxy)
+    private static B2ShapeProxy TransformShapeProxy(in B2Transform t, ref B2ShapeProxy proxy)
     {
         B2ShapeProxy ret = new B2ShapeProxy();
         ret.count = proxy.count;
diff --git a/src/Box2D.NET/B2DistanceJoints.cs b/src/Box2D.NET/B2DistanceJoints.cs
index f40c0620..157efd4c 100644
--- a/src/Box2D.NET/B2DistanceJoints.cs
+++ b/src/Box2D.NET/B2DistanceJoints.cs
@@ -547,7 +547,7 @@ internal static void b2SolveDistanceJoint(B2JointSim @base, B2StepContext contex
     }
 #endif
 
-        internal static void b2DrawDistanceJoint(B2DebugDraw draw, B2JointSim @base, B2Transform transformA, B2Transform transformB)
+        internal static void b2DrawDistanceJoint(B2DebugDraw draw, B2JointSim @base, in B2Transform transformA, in B2Transform transformB)
         {
             B2_ASSERT(@base.type == B2JointType.b2_distanceJoint);
 
diff --git a/src/Box2D.NET/B2Geometries.cs b/src/Box2D.NET/B2Geometries.cs
index 2a710710..4b903324 100644
--- a/src/Box2D.NET/B2Geometries.cs
+++ b/src/Box2D.NET/B2Geometries.cs
@@ -477,7 +477,7 @@ public static B2AABB b2ComputePolygonAABB(in B2Polygon shape, in B2Transform xf)
         }
 
         /// Compute the bounding box of a transformed line segment
-        public static B2AABB b2ComputeSegmentAABB(in B2Segment shape, B2Transform xf)
+        public static B2AABB b2ComputeSegmentAABB(in B2Segment shape, in B2Transform xf)
         {
             B2Vec2 v1 = b2TransformPoint(xf, shape.point1);
             B2Vec2 v2 = b2TransformPoint(xf, shape.point2);
diff --git a/src/Box2D.NET/B2Joints.cs b/src/Box2D.NET/B2Joints.cs
index 709f9b58..699e0369 100644
--- a/src/Box2D.NET/B2Joints.cs
+++ b/src/Box2D.NET/B2Joints.cs
@@ -790,7 +790,7 @@ public static B2WorldId b2Joint_GetWorld(B2JointId jointId)
         }
 
         /// Set the local frame on bodyA
-        public static void b2Joint_SetLocalFrameA(B2JointId jointId, B2Transform localFrame)
+        public static void b2Joint_SetLocalFrameA(B2JointId jointId, in B2Transform localFrame)
         {
             B2_ASSERT(b2IsValidTransform(localFrame));
 
@@ -810,7 +810,7 @@ public static B2Transform b2Joint_GetLocalFrameA(B2JointId jointId)
         }
 
         /// Set the local frame on bodyB
-        public static void b2Joint_SetLocalFrameB(B2JointId jointId, B2Transform localFrame)
+        public static void b2Joint_SetLocalFrameB(B2JointId jointId, in B2Transform localFrame)
         {
             B2_ASSERT(b2IsValidTransform(localFrame));
 
diff --git a/src/Box2D.NET/B2Manifolds.cs b/src/Box2D.NET/B2Manifolds.cs
index 15687d66..9c83aba4 100644
--- a/src/Box2D.NET/B2Manifolds.cs
+++ b/src/Box2D.NET/B2Manifolds.cs
@@ -42,7 +42,7 @@ public static B2Polygon b2MakeCapsule(B2Vec2 p1, B2Vec2 p2, float radius)
         // localAnchorB = qBc * (point - pB)
         // anchorB = point - pB = qA * localAnchorA + pA - pB
         //         = anchorA + (pA - pB)
-        public static B2Manifold b2CollideCircles(ref B2Circle circleA, B2Transform xfA, ref B2Circle circleB, B2Transform xfB)
+        public static B2Manifold b2CollideCircles(ref B2Circle circleA, in B2Transform xfA, ref B2Circle circleB, in B2Transform xfB)
         {
             B2Manifold manifold = new B2Manifold();
 
@@ -80,7 +80,7 @@ public static B2Manifold b2CollideCircles(ref B2Circle circleA, B2Transform xfA,
 
         /// Compute the contact manifold between a capsule and circle
         /// Compute the collision manifold between a capsule and circle
-        public static B2Manifold b2CollideCapsuleAndCircle(in B2Capsule capsuleA, B2Transform xfA, ref B2Circle circleB, B2Transform xfB)
+        public static B2Manifold b2CollideCapsuleAndCircle(in B2Capsule capsuleA, in B2Transform xfA, ref B2Circle circleB, in B2Transform xfB)
         {
             B2Manifold manifold = new B2Manifold();
 
@@ -145,7 +145,7 @@ public static B2Manifold b2CollideCapsuleAndCircle(in B2Capsule capsuleA, B2Tran
         }
 
         /// Compute the contact manifold between a polygon and a circle
-        public static B2Manifold b2CollidePolygonAndCircle(ref B2Polygon polygonA, B2Transform xfA, ref B2Circle circleB, B2Transform xfB)
+        public static B2Manifold b2CollidePolygonAndCircle(ref B2Polygon polygonA, in B2Transform xfA, ref B2Circle circleB, in B2Transform xfB)
         {
             B2Manifold manifold = new B2Manifold();
             float speculativeDistance = B2_SPECULATIVE_DISTANCE;
@@ -266,7 +266,7 @@ public static B2Manifold b2CollidePolygonAndCircle(ref B2Polygon polygonA, B2Tra
         /// Compute the contact manifold between a capsule and circle
         // Follows Ericson 5.1.9 Closest Points of Two Line Segments
         // Adds some logic to support clipping to get two contact points
-        public static B2Manifold b2CollideCapsules(in B2Capsule capsuleA, B2Transform xfA, in B2Capsule capsuleB, B2Transform xfB)
+        public static B2Manifold b2CollideCapsules(in B2Capsule capsuleA, in B2Transform xfA, in B2Capsule capsuleB, in B2Transform xfB)
         {
             B2Vec2 origin = capsuleA.center1;
 
@@ -537,14 +537,14 @@ public static B2Manifold b2CollideCapsules(in B2Capsule capsuleA, B2Transform xf
         }
 
         /// Compute the contact manifold between an segment and a capsule
-        public static B2Manifold b2CollideSegmentAndCapsule(ref B2Segment segmentA, B2Transform xfA, in B2Capsule capsuleB, B2Transform xfB)
+        public static B2Manifold b2CollideSegmentAndCapsule(ref B2Segment segmentA, in B2Transform xfA, in B2Capsule capsuleB, in B2Transform xfB)
         {
             B2Capsule capsuleA = new B2Capsule(segmentA.point1, segmentA.point2, 0.0f);
             return b2CollideCapsules(capsuleA, xfA, capsuleB, xfB);
         }
 
         /// Compute the contact manifold between a polygon and capsule
-        public static B2Manifold b2CollidePolygonAndCapsule(ref B2Polygon polygonA, B2Transform xfA, in B2Capsule capsuleB, B2Transform xfB)
+        public static B2Manifold b2CollidePolygonAndCapsule(ref B2Polygon polygonA, in B2Transform xfA, in B2Capsule capsuleB, in B2Transform xfB)
         {
             B2Polygon polyB = b2MakeCapsule(capsuleB.center1, capsuleB.center2, capsuleB.radius);
             return b2CollidePolygons(ref polygonA, xfA, ref polyB, xfB);
@@ -742,7 +742,7 @@ internal static float b2FindMaxSeparation(ref int edgeIndex, ref B2Polygon poly1
         // else
         //   clip edges
         // end
-        public static B2Manifold b2CollidePolygons(ref B2Polygon polygonA, B2Transform xfA, ref B2Polygon polygonB, B2Transform xfB)
+        public static B2Manifold b2CollidePolygons(ref B2Polygon polygonA, in B2Transform xfA, ref B2Polygon polygonB, in B2Transform xfB)
         {
             B2Vec2 origin = polygonA.vertices[0];
             float linearSlop = B2_LINEAR_SLOP;
@@ -1088,21 +1088,21 @@ public static B2Manifold b2CollidePolygons(ref B2Polygon polygonA, B2Transform x
         }
 
         /// Compute the contact manifold between an segment and a circle
-        public static B2Manifold b2CollideSegmentAndCircle(ref B2Segment segmentA, B2Transform xfA, ref B2Circle circleB, B2Transform xfB)
+        public static B2Manifold b2CollideSegmentAndCircle(ref B2Segment segmentA, in B2Transform xfA, ref B2Circle circleB, in B2Transform xfB)
         {
             B2Capsule capsuleA = new B2Capsule(segmentA.point1, segmentA.point2, 0.0f);
             return b2CollideCapsuleAndCircle(capsuleA, xfA, ref circleB, xfB);
         }
 
         /// Compute the contact manifold between an segment and a polygon
-        public static B2Manifold b2CollideSegmentAndPolygon(ref B2Segment segmentA, B2Transform xfA, ref B2Polygon polygonB, B2Transform xfB)
+        public static B2Manifold b2CollideSegmentAndPolygon(ref B2Segment segmentA, in B2Transform xfA, ref B2Polygon polygonB, in B2Transform xfB)
         {
             B2Polygon polygonA = b2MakeCapsule(segmentA.point1, segmentA.point2, 0.0f);
             return b2CollidePolygons(ref polygonA, xfA, ref polygonB, xfB);
         }
 
         /// Compute the contact manifold between a chain segment and a circle
-        public static B2Manifold b2CollideChainSegmentAndCircle(ref B2ChainSegment segmentA, B2Transform xfA, ref B2Circle circleB, B2Transform xfB)
+        public static B2Manifold b2CollideChainSegmentAndCircle(ref B2ChainSegment segmentA, in B2Transform xfA, ref B2Circle circleB, in B2Transform xfB)
         {
             B2Manifold manifold = new B2Manifold();
 
@@ -1190,7 +1190,7 @@ public static B2Manifold b2CollideChainSegmentAndCircle(ref B2ChainSegment segme
         }
 
         /// Compute the contact manifold between a chain segment and a capsule
-        public static B2Manifold b2CollideChainSegmentAndCapsule(ref B2ChainSegment segmentA, B2Transform xfA, in B2Capsule capsuleB, B2Transform xfB, ref B2SimplexCache cache)
+        public static B2Manifold b2CollideChainSegmentAndCapsule(ref B2ChainSegment segmentA, in B2Transform xfA, in B2Capsule capsuleB, in B2Transform xfB, ref B2SimplexCache cache)
         {
             B2Polygon polyB = b2MakeCapsule(capsuleB.center1, capsuleB.center2, capsuleB.radius);
             return b2CollideChainSegmentAndPolygon(ref segmentA, xfA, ref polyB, xfB, ref cache);
@@ -1311,7 +1311,7 @@ internal static B2NormalType b2ClassifyNormal(B2ChainSegmentParams param, B2Vec2
         }
 
         /// Compute the contact manifold between a chain segment and a rounded polygon
-        public static B2Manifold b2CollideChainSegmentAndPolygon(ref B2ChainSegment segmentA, B2Transform xfA, ref B2Polygon polygonB,
+        public static B2Manifold b2CollideChainSegmentAndPolygon(ref B2ChainSegment segmentA, in B2Transform xfA, ref B2Polygon polygonB,
             B2Transform xfB, ref B2SimplexCache cache)
         {
             B2Manifold manifold = new B2Manifold();
diff --git a/src/Box2D.NET/B2PrismaticJoints.cs b/src/Box2D.NET/B2PrismaticJoints.cs
index 7f589938..5a82f7cc 100644
--- a/src/Box2D.NET/B2PrismaticJoints.cs
+++ b/src/Box2D.NET/B2PrismaticJoints.cs
@@ -679,7 +679,7 @@ internal static void b2SolvePrismaticJoint(B2JointSim @base, B2StepContext conte
         }
 #endif
 
-        internal static void b2DrawPrismaticJoint(B2DebugDraw draw, B2JointSim @base, B2Transform transformA, B2Transform transformB, float drawScale)
+        internal static void b2DrawPrismaticJoint(B2DebugDraw draw, B2JointSim @base, in B2Transform transformA, in B2Transform transformB, float drawScale)
         {
             B2_ASSERT(@base.type == B2JointType.b2_prismaticJoint);
 
diff --git a/src/Box2D.NET/B2RevoluteJoints.cs b/src/Box2D.NET/B2RevoluteJoints.cs
index 392fb377..1a35d1e9 100644
--- a/src/Box2D.NET/B2RevoluteJoints.cs
+++ b/src/Box2D.NET/B2RevoluteJoints.cs
@@ -512,7 +512,7 @@ internal static void b2SolveRevoluteJoint(B2JointSim @base, B2StepContext contex
     }
 #endif
 
-        internal static void b2DrawRevoluteJoint(B2DebugDraw draw, B2JointSim @base, B2Transform transformA, B2Transform transformB, float drawScale)
+        internal static void b2DrawRevoluteJoint(B2DebugDraw draw, B2JointSim @base, in B2Transform transformA, in B2Transform transformB, float drawScale)
         {
             B2_ASSERT(@base.type == B2JointType.b2_revoluteJoint);
 
diff --git a/src/Box2D.NET/B2Shapes.cs b/src/Box2D.NET/B2Shapes.cs
index bbb6aac4..6a136935 100644
--- a/src/Box2D.NET/B2Shapes.cs
+++ b/src/Box2D.NET/B2Shapes.cs
@@ -74,7 +74,7 @@ internal static B2ChainShape b2GetChainShape(B2World world, B2ChainId chainId)
             return chain;
         }
 
-        internal static void b2UpdateShapeAABBs(B2Shape shape, B2Transform transform, B2BodyType proxyType)
+        internal static void b2UpdateShapeAABBs(B2Shape shape, in B2Transform transform, B2BodyType proxyType)
         {
             // Compute a bounding box with a speculative margin
             float speculativeDistance = B2_SPECULATIVE_DISTANCE;
@@ -836,7 +836,7 @@ internal static B2ShapeExtent b2ComputeShapeExtent(B2Shape shape, B2Vec2 localCe
             return extent;
         }
 
-        internal static B2CastOutput b2RayCastShape(in B2RayCastInput input, B2Shape shape, B2Transform transform)
+        internal static B2CastOutput b2RayCastShape(in B2RayCastInput input, B2Shape shape, in B2Transform transform)
         {
             B2RayCastInput localInput = input;
             localInput.origin = b2InvTransformPoint(transform, input.origin);
@@ -869,7 +869,7 @@ internal static B2CastOutput b2RayCastShape(in B2RayCastInput input, B2Shape sha
             return output;
         }
 
-        internal static B2CastOutput b2ShapeCastShape(in B2ShapeCastInput input, B2Shape shape, B2Transform transform)
+        internal static B2CastOutput b2ShapeCastShape(in B2ShapeCastInput input, B2Shape shape, in B2Transform transform)
         {
             B2CastOutput output = new B2CastOutput();
 
@@ -933,7 +933,7 @@ internal static B2CastOutput b2ShapeCastShape(in B2ShapeCastInput input, B2Shape
             return output;
         }
 
-        internal static B2PlaneResult b2CollideMover(in B2Capsule mover, B2Shape shape, B2Transform transform)
+        internal static B2PlaneResult b2CollideMover(in B2Capsule mover, B2Shape shape, in B2Transform transform)
         {
             B2Capsule localMover = new B2Capsule();
             localMover.center1 = b2InvTransformPoint(transform, mover.center1);
@@ -972,7 +972,7 @@ internal static B2PlaneResult b2CollideMover(in B2Capsule mover, B2Shape shape,
         }
 
 
-        public static void b2CreateShapeProxy(B2Shape shape, B2BroadPhase bp, B2BodyType type, B2Transform transform, bool forcePairCreation)
+        public static void b2CreateShapeProxy(B2Shape shape, B2BroadPhase bp, B2BodyType type, in B2Transform transform, bool forcePairCreation)
         {
             B2_ASSERT(shape.proxyKey == B2_NULL_INDEX);
 
diff --git a/src/Box2D.NET/B2WeldJoints.cs b/src/Box2D.NET/B2WeldJoints.cs
index 600ebcf0..735bfba2 100644
--- a/src/Box2D.NET/B2WeldJoints.cs
+++ b/src/Box2D.NET/B2WeldJoints.cs
@@ -489,7 +489,7 @@ internal static void b2DumpWeldJoint()
         }
 #endif
 
-        internal static void b2DrawWeldJoint(B2DebugDraw draw, B2JointSim @base, B2Transform transformA, B2Transform transformB, float drawScale)
+        internal static void b2DrawWeldJoint(B2DebugDraw draw, B2JointSim @base, in B2Transform transformA, in B2Transform transformB, float drawScale)
         {
             B2_ASSERT(@base.type == B2JointType.b2_weldJoint);
 
diff --git a/src/Box2D.NET/B2WheelJoints.cs b/src/Box2D.NET/B2WheelJoints.cs
index 2664dfe0..fe5d176d 100644
--- a/src/Box2D.NET/B2WheelJoints.cs
+++ b/src/Box2D.NET/B2WheelJoints.cs
@@ -536,7 +536,7 @@ void b2WheelJoint_Dump()
     }
 #endif
 
-        internal static void b2DrawWheelJoint(B2DebugDraw draw, B2JointSim @base, B2Transform transformA, B2Transform transformB, float drawScale)
+        internal static void b2DrawWheelJoint(B2DebugDraw draw, B2JointSim @base, in B2Transform transformA, in B2Transform transformB, float drawScale)
         {
             B2_ASSERT(@base.type == B2JointType.b2_wheelJoint);