Constraint which prevents the connected entities from rotating relative to each other around an axis beyond given limits.
Inheritance: JointLimit, I2DImpulseConstraintWithError, I2DJacobianConstraint
Exemple #1
0
        /// <summary>
        /// Constructs a new constraint which restricts three degrees of linear freedom and one degree of angular freedom between two entities.
        /// </summary>
        /// <param name="connectionA">First entity of the constraint pair.</param>
        /// <param name="connectionB">Second entity of the constraint pair.</param>
        /// <param name="anchor">Point around which both entities rotate.</param>
        /// <param name="hingeAxis">Axis of allowed rotation in world space to be attached to connectionA.  Will be kept perpendicular with the twist axis.</param>
        public SwivelHingeJoint(Entity connectionA, Entity connectionB, ref Vector3 anchor, ref Vector3 hingeAxis)
        {
            if (connectionA == null)
                connectionA = TwoEntityConstraint.WorldEntity;
            if (connectionB == null)
                connectionB = TwoEntityConstraint.WorldEntity;
            BallSocketJoint = new BallSocketJoint(connectionA, connectionB, ref anchor);
			Vector3 tmp;
			BallSocketJoint.OffsetB.Invert( out tmp );
            AngularJoint = new SwivelHingeAngularJoint(connectionA, connectionB, ref hingeAxis, ref tmp );
            HingeLimit = new RevoluteLimit(connectionA, connectionB);
            HingeMotor = new RevoluteMotor(connectionA, connectionB, hingeAxis);
            TwistLimit = new TwistLimit(connectionA, connectionB, ref BallSocketJoint.worldOffsetA, ref tmp, 0, 0);
            TwistMotor = new TwistMotor(connectionA, connectionB, ref BallSocketJoint.worldOffsetA, ref tmp );
            HingeLimit.IsActive = false;
            HingeMotor.IsActive = false;
            TwistLimit.IsActive = false;
            TwistMotor.IsActive = false;

			//Ensure that the base and test direction is perpendicular to the free axis.
			Vector3 baseAxis; anchor.Sub( ref connectionA.position, out baseAxis );
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) //anchor and connection a in same spot, so try the other way.
                connectionB.position.Sub( ref anchor, out baseAxis );
            baseAxis.AddScaled( ref hingeAxis, -Vector3.Dot( ref baseAxis, ref hingeAxis) , out baseAxis );
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                Vector3.Cross(ref hingeAxis, ref Vector3.Up, out baseAxis);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    Vector3.Cross(ref hingeAxis, ref Vector3.Right, out baseAxis);
                }
            }
            HingeLimit.Basis.SetWorldAxes(ref hingeAxis, ref baseAxis, ref connectionA.orientationMatrix);
            HingeMotor.Basis.SetWorldAxes( ref hingeAxis, ref baseAxis, ref connectionA.orientationMatrix);

			connectionB.position.Sub( ref anchor, out baseAxis );
            baseAxis.AddScaled( ref hingeAxis, -Vector3.Dot(ref baseAxis, ref hingeAxis), out baseAxis );
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                Vector3.Cross(ref hingeAxis, ref Vector3.Up, out baseAxis);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    Vector3.Cross(ref hingeAxis, ref Vector3.Right, out baseAxis);
                }
            }
            HingeLimit.TestAxis = baseAxis;
            HingeMotor.TestAxis = baseAxis;


            Add(BallSocketJoint);
            Add(AngularJoint);
            Add(HingeLimit);
            Add(HingeMotor);
            Add(TwistLimit);
            Add(TwistMotor);
        }
Exemple #2
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        /// <summary>
        /// Constructs a new constraint which restricts three degrees of linear freedom and one degree of angular freedom between two entities.
        /// </summary>
        /// <param name="connectionA">First entity of the constraint pair.</param>
        /// <param name="connectionB">Second entity of the constraint pair.</param>
        /// <param name="anchor">Point around which both entities rotate.</param>
        /// <param name="hingeAxis">Axis of allowed rotation in world space to be attached to connectionA.  Will be kept perpendicular with the twist axis.</param>
        public SwivelHingeJoint(Entity connectionA, Entity connectionB, Vector3 anchor, Vector3 hingeAxis)
        {
            if (connectionA == null)
                connectionA = TwoEntityConstraint.WorldEntity;
            if (connectionB == null)
                connectionB = TwoEntityConstraint.WorldEntity;
            BallSocketJoint = new BallSocketJoint(connectionA, connectionB, anchor);
            AngularJoint = new SwivelHingeAngularJoint(connectionA, connectionB, hingeAxis, -BallSocketJoint.OffsetB);
            HingeLimit = new RevoluteLimit(connectionA, connectionB);
            HingeMotor = new RevoluteMotor(connectionA, connectionB, hingeAxis);
            TwistLimit = new TwistLimit(connectionA, connectionB, BallSocketJoint.OffsetA, -BallSocketJoint.OffsetB, 0, 0);
            TwistMotor = new TwistMotor(connectionA, connectionB, BallSocketJoint.OffsetA, -BallSocketJoint.OffsetB);
            HingeLimit.IsActive = false;
            HingeMotor.IsActive = false;
            TwistLimit.IsActive = false;
            TwistMotor.IsActive = false;

            //Ensure that the base and test direction is perpendicular to the free axis.
            Vector3 baseAxis = anchor - connectionA.position;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) //anchor and connection a in same spot, so try the other way.
                baseAxis = connectionB.position - anchor;
            baseAxis -= Vector3.Dot(baseAxis, hingeAxis) * hingeAxis;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                baseAxis = Vector3.Cross(hingeAxis, Vector3.Up);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    baseAxis = Vector3.Cross(hingeAxis, Vector3.Right);
                }
            }
            HingeLimit.Basis.SetWorldAxes(hingeAxis, baseAxis, connectionA.orientationMatrix);
            HingeMotor.Basis.SetWorldAxes(hingeAxis, baseAxis, connectionA.orientationMatrix);

            baseAxis = connectionB.position - anchor;
            baseAxis -= Vector3.Dot(baseAxis, hingeAxis) * hingeAxis;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                baseAxis = Vector3.Cross(hingeAxis, Vector3.Up);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    baseAxis = Vector3.Cross(hingeAxis, Vector3.Right);
                }
            }
            HingeLimit.TestAxis = baseAxis;
            HingeMotor.TestAxis = baseAxis;


            Add(BallSocketJoint);
            Add(AngularJoint);
            Add(HingeLimit);
            Add(HingeMotor);
            Add(TwistLimit);
            Add(TwistMotor);
        }
Exemple #3
0
        /// <summary>
        /// Constructs a new constraint which restricts three degrees of linear freedom and two degrees of angular freedom between two entities.
        /// This constructs the internal constraints, but does not configure them.  Before using a constraint constructed in this manner,
        /// ensure that its active constituent constraints are properly configured.  The entire group as well as all internal constraints are initially inactive (IsActive = false).
        /// </summary>
        public RevoluteJoint()
        {
            IsActive = false;
            BallSocketJoint = new BallSocketJoint();
            AngularJoint = new RevoluteAngularJoint();
            Limit = new RevoluteLimit();
            Motor = new RevoluteMotor();

            Add(BallSocketJoint);
            Add(AngularJoint);
            Add(Limit);
            Add(Motor);
        }
Exemple #4
0
        /// <summary>
        /// Constructs a new constraint which restricts three degrees of linear freedom and two degrees of angular freedom between two entities.
        /// </summary>
        /// <param name="connectionA">First entity of the constraint pair.</param>
        /// <param name="connectionB">Second entity of the constraint pair.</param>
        /// <param name="anchor">Point around which both entities rotate.</param>
        /// <param name="freeAxis">Axis around which the hinge can rotate.</param>
        public RevoluteJoint(Entity connectionA, Entity connectionB, System.Numerics.Vector3 anchor, System.Numerics.Vector3 freeAxis)
        {
            if (connectionA == null)
                connectionA = TwoEntityConstraint.WorldEntity;
            if (connectionB == null)
                connectionB = TwoEntityConstraint.WorldEntity;
            BallSocketJoint = new BallSocketJoint(connectionA, connectionB, anchor);
            AngularJoint = new RevoluteAngularJoint(connectionA, connectionB, freeAxis);
            Limit = new RevoluteLimit(connectionA, connectionB);
            Motor = new RevoluteMotor(connectionA, connectionB, freeAxis);
            Limit.IsActive = false;
            Motor.IsActive = false;

            //Ensure that the base and test direction is perpendicular to the free axis.
            System.Numerics.Vector3 baseAxis = anchor - connectionA.position;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) //anchor and connection a in same spot, so try the other way.
                baseAxis = connectionB.position - anchor;
            baseAxis -= Vector3Ex.Dot(baseAxis, freeAxis) * freeAxis;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                baseAxis = System.Numerics.Vector3.Cross(freeAxis, Vector3Ex.Up);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    baseAxis = System.Numerics.Vector3.Cross(freeAxis, Vector3Ex.Right);
                }
            }
            Limit.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix);
            Motor.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix);

            baseAxis = connectionB.position - anchor;
            baseAxis -= Vector3Ex.Dot(baseAxis, freeAxis) * freeAxis;
            if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
            {
                //However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
                baseAxis = System.Numerics.Vector3.Cross(freeAxis, Vector3Ex.Up);
                if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
                {
                    baseAxis = System.Numerics.Vector3.Cross(freeAxis, Vector3Ex.Right);
                }
            }
            Limit.TestAxis = baseAxis;
            Motor.TestAxis = baseAxis;

            Add(BallSocketJoint);
            Add(AngularJoint);
            Add(Limit);
            Add(Motor);
        }
        /// <summary>
        /// Constructs a new constraint which restricts three degrees of linear freedom and one degree of angular freedom between two entities.
        /// This constructs the internal constraints, but does not configure them.  Before using a constraint constructed in this manner,
        /// ensure that its active constituent constraints are properly configured.  The entire group as well as all internal constraints are initially inactive (IsActive = false).
        /// </summary>
        public SwivelHingeJoint()
        {
            IsActive = false;
            BallSocketJoint = new BallSocketJoint();
            AngularJoint = new SwivelHingeAngularJoint();
            HingeLimit = new RevoluteLimit();
            HingeMotor = new RevoluteMotor();
            TwistLimit = new TwistLimit();
            TwistMotor = new TwistMotor();

            Add(BallSocketJoint);
            Add(AngularJoint);
            Add(HingeLimit);
            Add(HingeMotor);
            Add(TwistLimit);
            Add(TwistMotor);
        }
        Entity AddDriveWheel(Vector3 wheelOffset, Entity body, out RevoluteMotor drivingMotor, out RevoluteMotor steeringMotor)
        {
            var wheel = new Cylinder(body.Position + wheelOffset, .4f, .5f, 5f);
            wheel.Material.KineticFriction = 2.5f;
            wheel.Material.StaticFriction = 3.5f;
            wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);

            //Preventing the occasional pointless collision pair can speed things up.
            CollisionRules.AddRule(wheel, body, CollisionRule.NoBroadPhase);

            //Connect the wheel to the body.
            var pointOnLineJoint = new PointOnLineJoint(body, wheel, wheel.Position, Vector3.Down, wheel.Position);
            var suspensionLimit = new LinearAxisLimit(body, wheel, wheel.Position, wheel.Position, Vector3.Down, -1, 0);
            //This linear axis motor will give the suspension its springiness by pushing the wheels outward.
            var suspensionSpring = new LinearAxisMotor(body, wheel, wheel.Position, wheel.Position, Vector3.Down);
            suspensionSpring.Settings.Mode = MotorMode.Servomechanism;
            suspensionSpring.Settings.Servo.Goal = 0;
            suspensionSpring.Settings.Servo.SpringSettings.Stiffness = 300;
            suspensionSpring.Settings.Servo.SpringSettings.Damping = 70;

            var swivelHingeAngularJoint = new SwivelHingeAngularJoint(body, wheel, Vector3.Up, Vector3.Right);
            //Motorize the wheel.
            drivingMotor = new RevoluteMotor(body, wheel, Vector3.Left);
            drivingMotor.Settings.VelocityMotor.Softness = .3f;
            drivingMotor.Settings.MaximumForce = 100;
            //Let it roll when the user isn't giving specific commands.
            drivingMotor.IsActive = false;
            steeringMotor = new RevoluteMotor(body, wheel, Vector3.Up);
            steeringMotor.Settings.Mode = MotorMode.Servomechanism;
            //The constructor makes a guess about how to set up the constraint.
            //It can't always be right since it doesn't have all the information;
            //in this case, it chooses the basis and test axis incorrectly.
            //This leads to a 'flipping' behavior when the wheel is rolling
            //(the test axis is 'rolling' with the wheel, and passes over
            //a singularity which causes a flip).

            //To fix this, we configure the constraint directly.
            //The basis is aligned with how the wheel is set up; we choose 'up' as 
            //the motorized axis, and right/forward to define the angle measurement plane.
            //The test axis is set to be perpendicular to the wheel's rotation so that
            //it only measures the steering angle.

            //If you're curious, the angle measurement is just a Math.Atan2.
            //The current world test axis is dotted against the two plane axes (Right and Forward here).
            //This gives an x and y value.  These can be plugged into Atan2 just like when
            //you compute an angle on a normal 2d graph.
            steeringMotor.Basis.SetWorldAxes(Vector3.Up, Vector3.Right);
            steeringMotor.TestAxis = Vector3.Right;

            steeringMotor.Settings.Servo.BaseCorrectiveSpeed = 5;


            //The revolute motor is weaker than some other types of constraints and maintaining a goal in the presence of extremely fast rotation and integration issues.
            //Laying a revolute limit on top of it can help mitigate the problem.
            var steeringConstraint = new RevoluteLimit(body, wheel, Vector3.Up, Vector3.Right, -maximumTurnAngle, maximumTurnAngle);

    
            //Add the wheel and connection to the space.
            Space.Add(wheel);
            Space.Add(pointOnLineJoint);
            Space.Add(suspensionLimit);
            Space.Add(suspensionSpring);
            Space.Add(swivelHingeAngularJoint);
            Space.Add(drivingMotor);
            Space.Add(steeringMotor); 
            Space.Add(steeringConstraint);

            return wheel;
        }
        public JointLimitTestDemo(DemosGame game)
            : base(game)
        {
            float bounciness = 1;
            float baseMass = 100;
            float armMass = 10;
            //DistanceLimit
            Box boxA = new Box(new Vector3(-21, 4, 0), 3, 3, 3, baseMass);
            Box boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            var distanceLimit = new DistanceLimit(boxA, boxB, boxA.Position, boxB.Position - new Vector3(0, 2, 0), 1, 6);
            distanceLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(distanceLimit);

            //EllipseSwingLimit
            boxA = new Box(new Vector3(-14, 4, 0), 3, 3, 3, baseMass);
            boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            var ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
            var ellipseSwingLimit = new EllipseSwingLimit(boxA, boxB, Vector3.Up, MathHelper.Pi / 1.5f, MathHelper.Pi / 3);
            ellipseSwingLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(ballSocketJoint);
            Space.Add(ellipseSwingLimit);

            //LinearAxisLimit
            boxA = new Box(new Vector3(-7, 4, 0), 3, 3, 3, baseMass);
            boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            var pointOnLineJoint = new PointOnLineJoint(boxA, boxB, boxA.Position, Vector3.Up, boxB.Position + new Vector3(0, -2, 0));
            var linearAxisLimit = new LinearAxisLimit(boxA, boxB, boxA.Position, boxB.Position + new Vector3(0, -2, 0), Vector3.Up, 0, 4);
            linearAxisLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(pointOnLineJoint);
            Space.Add(linearAxisLimit);

            //RevoluteLimit
            boxA = new Box(new Vector3(0, 4, 0), 3, 3, 3, baseMass);
            boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
            var revoluteAngularJoint = new RevoluteAngularJoint(boxA, boxB, Vector3.Forward);
            var revoluteLimit = new RevoluteLimit(boxA, boxB, Vector3.Forward, Vector3.Up, -MathHelper.PiOver4, MathHelper.PiOver4);
            revoluteLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(ballSocketJoint);
            Space.Add(revoluteAngularJoint);
            Space.Add(revoluteLimit);

            //SwingLimit
            boxA = new Box(new Vector3(7, 4, 0), 3, 3, 3, baseMass);
            boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
            var swingLimit = new SwingLimit(boxA, boxB, Vector3.Up, Vector3.Up, MathHelper.PiOver4);
            swingLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(ballSocketJoint);
            Space.Add(swingLimit);

            //TwistLimit
            boxA = new Box(new Vector3(14, 4, 0), 3, 3, 3, baseMass);
            boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
            CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
            boxB.ActivityInformation.IsAlwaysActive = true;

            ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
            revoluteAngularJoint = new RevoluteAngularJoint(boxA, boxB, Vector3.Up);
            var twistLimit = new TwistLimit(boxA, boxB, Vector3.Up, Vector3.Up, -MathHelper.PiOver4, MathHelper.PiOver4);
            twistLimit.Bounciness = bounciness;

            Space.Add(boxA);
            Space.Add(boxB);
            Space.Add(ballSocketJoint);
            Space.Add(revoluteAngularJoint);
            Space.Add(twistLimit);

            Space.Add(new Box(new Vector3(0, 0, 0), 60, 1, 60));
            game.Camera.Position = new Vector3(0, 6, 15);
        }
        void AddDriveWheel(Vector3 suspensionOffset, Entity body, bool leftSide, out RevoluteMotor drivingMotor, out RevoluteMotor steeringMotor, out Box suspensionLeg)
        {
            suspensionLeg = new Box(body.Position + suspensionOffset, 0.25f, 0.8f, 0.25f, 10);

            const float horizontalWheelOffset = 0.2f;

            var wheel = new Cylinder(suspensionLeg.Position + new Vector3(leftSide ? -horizontalWheelOffset : horizontalWheelOffset, -suspensionLeg.HalfHeight, 0), .2f, .3f, 5f);
            wheel.Material.KineticFriction = 2.5f;
            wheel.Material.StaticFriction = 3.5f;
            wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);

            //Preventing the occasional pointless collision pair can speed things up.
            CollisionRules.AddRule(wheel, body, CollisionRule.NoBroadPhase);
            CollisionRules.AddRule(wheel, suspensionLeg, CollisionRule.NoBroadPhase);
            CollisionRules.AddRule(suspensionLeg, body, CollisionRule.NoBroadPhase);

            //Connect the suspension to the body.
            var bodyToSuspension = new LineSliderJoint(body, suspensionLeg, suspensionLeg.Position, Vector3.Down, suspensionLeg.Position);
            bodyToSuspension.Limit.IsActive = true;
            bodyToSuspension.Limit.Minimum = -0.5f;
            bodyToSuspension.Limit.Maximum = 0;

            //This linear axis motor will give the suspension its springiness by pushing the wheels outward.
            bodyToSuspension.Motor.IsActive = true;
            bodyToSuspension.Motor.Settings.Mode = MotorMode.Servomechanism;
            bodyToSuspension.Motor.Settings.Servo.Goal = 0;
            bodyToSuspension.Motor.Settings.Servo.SpringSettings.Stiffness = 300;
            bodyToSuspension.Motor.Settings.Servo.SpringSettings.Damping = 70;

            steeringMotor = new RevoluteMotor(body, suspensionLeg, Vector3.Up);
            steeringMotor.Settings.Mode = MotorMode.Servomechanism;
            //The constructor makes a guess about how to set up the constraint.
            //It can't always be right since it doesn't have all the information;
            //in this case, it chooses the basis and test axis incorrectly.
            //This leads to a 'flipping' behavior when the wheel is rolling
            //(the test axis is 'rolling' with the wheel, and passes over
            //a singularity which causes a flip).

            //To fix this, we configure the constraint directly.
            //The basis is aligned with how the wheel is set up; we choose 'up' as
            //the motorized axis, and right/forward to define the angle measurement plane.
            //The test axis is set to be perpendicular to the wheel's rotation so that
            //it only measures the steering angle.

            //If you're curious, the angle measurement is just a Math.Atan2.
            //The current world test axis is dotted against the two plane axes (Right and Forward here).
            //This gives an x and y value.  These can be plugged into Atan2 just like when
            //you compute an angle on a normal 2d graph.
            steeringMotor.Basis.SetWorldAxes(Vector3.Up, Vector3.Right);
            steeringMotor.TestAxis = Vector3.Right;

            //To make the steering a little more responsive, set a base speed at which error gets corrected.
            //This works on top of the default error reduction implied by the constraint's spring constants.
            steeringMotor.Settings.Servo.BaseCorrectiveSpeed = 1;

            //The revolute motor is weaker than some other types of constraints and maintaining a goal in the presence of extremely fast rotation and integration issues.
            //Laying a revolute limit on top of it can help mitigate the problem.
            var steeringConstraint = new RevoluteLimit(body, suspensionLeg, Vector3.Up, Vector3.Right, -maximumTurnAngle, maximumTurnAngle);

            //Connect the wheel to the suspension.
            var suspensionToWheel = new RevoluteJoint(suspensionLeg, wheel, wheel.Position, Vector3.Right);
            drivingMotor = suspensionToWheel.Motor;
            //The driving motor's default, created by the RevoluteJoint constructor above, chose the axis of rotation such that negatives values made the car go forward and vice versa.
            //Swap it around so that the positive values make the car roll forward instead!
            drivingMotor.Basis.SetWorldAxes(Vector3.Left, Vector3.Forward);
            drivingMotor.TestAxis = Vector3.Forward;
            drivingMotor.Settings.VelocityMotor.Softness = .3f;
            drivingMotor.Settings.MaximumForce = 100;

            //Add the wheel and connection to the space.
            Space.Add(wheel);
            Space.Add(suspensionLeg);
            Space.Add(bodyToSuspension);
            Space.Add(drivingMotor);
            Space.Add(steeringMotor);
            Space.Add(steeringConstraint);
            Space.Add(suspensionToWheel);
        }