not work

Code/Base/Wheel/Suspension/BasicSuspension.cs

@@ -0,0 +1,18 @@
+namespace VeloX;
+
+public class BasicSuspension
+{
+	private readonly Hinge Hinge;
+
+	public BasicSuspension( Vector3 wheel, Vector3 hingeBody, Vector3 hingeWheel )
+	{
+		Vector3 hingePoint = wheel - (hingeWheel - hingeBody);
+		Hinge = new Hinge( hingePoint, hingeWheel - hingeBody );
+	}
+
+	public virtual void GetWheelTransform( float travel, out Rotation rotation, out Vector3 position )
+	{
+		rotation = Rotation.Identity;
+		position = Hinge.Rotate( travel );
+	}
+}

Code/Base/Wheel/Suspension/Hinge.cs

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+using System;
+
+namespace VeloX;
+
+internal readonly struct Hinge( Vector3 hinge_anchor, Vector3 hinge_arm )
+{
+	[Description( "the point that the wheels are rotated around as the suspension compresses" )]
+	public readonly Vector3 Anchor = hinge_anchor;
+
+	[Description( "anchor to wheel vector" )]
+	public readonly Vector3 Arm = hinge_arm;
+
+	[Description( "arm length squared" )]
+	public readonly float LengthSquared = hinge_arm.Dot( hinge_arm );
+
+	[Description( "1 / arm length in hinge axis normal plane" )]
+	public readonly float NormXY = 1 / MathF.Sqrt( hinge_arm.x * hinge_arm.x + hinge_arm.y * hinge_arm.y );
+
+	public readonly Vector3 Rotate( float travel )
+	{
+		float z = Arm.z + travel;
+		float lengthSq = MathF.Max( LengthSquared - z * z, 0.0f );
+		float nxy = NormXY * MathF.Sqrt( lengthSq );
+		return Anchor + new Vector3( Arm.x * nxy, Arm.y * nxy, z );
+	}
+}

Code/Base/Wheel/Suspension/MacPhersonSuspension.cs

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+using Sandbox;
+using System;
+
+namespace VeloX;
+public class MacPhersonSuspension
+{
+	public readonly Vector3 WheelOffset;
+	public readonly Vector3 UprightTop;
+	public readonly Vector3 UprightAxis;
+	private readonly Hinge Hinge;
+
+	public MacPhersonSuspension( Vector3 wheel, Vector3 strutBody, Vector3 strutWheel, Vector3 hingeBody )
+	{
+		WheelOffset = wheel - strutWheel;
+		UprightTop = strutBody;
+		UprightAxis = (strutBody - strutWheel).Normal;
+		Hinge = new( hingeBody, strutWheel - hingeBody );
+	}
+
+	public void GetWheelTransform( float travel, out Rotation rotation, out Vector3 position )
+	{
+		Vector3 hingeEnd = Hinge.Rotate( travel );
+		Vector3 uprightAxisNew = (UprightTop - hingeEnd).Normal;
+
+		rotation = Rotation.FromAxis(
+			Vector3.Cross( UprightAxis, uprightAxisNew ),
+			MathF.Acos( Vector3.Dot( UprightAxis, uprightAxisNew ) ).RadianToDegree()
+		);
+
+		position = hingeEnd + WheelOffset.Transform( rotation );
+	}
+}