/// <summary> /// Constructs a new demo. /// </summary> /// <param name="game">Game owning this demo.</param> public SuspensionCarDemo2(DemosGame game) : base(game) { game.Camera.Position = new Vector3(0, 2, 15); Space.Add(new Box(new Vector3(0, -5, 0), 20, 1, 20)); var body = new Box(new Vector3(0, 0, 0), 2, .5f, 3, 20); body.CollisionInformation.LocalPosition = new Vector3(0, 1f, 0); Space.Add(body); AddBackWheel(new Vector3(-1f, .55f, 1.3f), body, true); AddBackWheel(new Vector3(1f, .55f, 1.3f), body, false); Box suspensionLeg1, suspensionLeg2; AddDriveWheel(new Vector3(-1f, .55f, -1.3f), body, true, out drivingMotor1, out steeringMotor1, out suspensionLeg1); AddDriveWheel(new Vector3(1f, .55f, -1.3f), body, false, out drivingMotor2, out steeringMotor2, out suspensionLeg2); //Add a stabilizer so that the wheels can't point different directions. var steeringStabilizer = new RevoluteAngularJoint(suspensionLeg1, suspensionLeg2, Vector3.Right); Space.Add(steeringStabilizer); //x and y, in terms of heightmaps, refer to their local x and y coordinates. In world space, they correspond to x and z. //Setup the heights of the terrain. int xLength = 180; int zLength = 180; float xSpacing = 8f; float zSpacing = 8f; var heights = new float[xLength, zLength]; for (int i = 0; i < xLength; i++) { for (int j = 0; j < zLength; j++) { float x = i - xLength / 2; float z = j - zLength / 2; //heights[i,j] = (float)(x * y / 1000f); heights[i, j] = (float)(10 * (Math.Sin(x / 8) + Math.Sin(z / 8))); //heights[i,j] = 3 * (float)Math.Sin(x * y / 100f); //heights[i,j] = (x * x * x * y - y * y * y * x) / 1000f; } } //Create the terrain. var terrain = new Terrain(heights, new AffineTransform( new Vector3(xSpacing, 1, zSpacing), Quaternion.Identity, new Vector3(-xLength * xSpacing / 2, -10, -zLength * zSpacing / 2))); //terrain.Thickness = 5; //Uncomment this and shoot some things at the bottom of the terrain! They'll be sucked up through the ground. Space.Add(terrain); game.ModelDrawer.Add(terrain); }
/// <summary> /// Constructs a new constraint which restricts two 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 LineSliderJoint() { IsActive = false; PointOnLineJoint = new PointOnLineJoint(); AngularJoint = new RevoluteAngularJoint(); Limit = new LinearAxisLimit(); Motor = new LinearAxisMotor(); Add(PointOnLineJoint); Add(AngularJoint); Add(Limit); Add(Motor); }
/// <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); }
/// <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, Vector3 anchor, 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. 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, 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 = Vector3.Cross(freeAxis, Vector3.Up); if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) { baseAxis = Vector3.Cross(freeAxis, Vector3.Right); } } Limit.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix); Motor.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix); baseAxis = connectionB.position - anchor; baseAxis -= Vector3.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 = Vector3.Cross(freeAxis, Vector3.Up); if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) { baseAxis = Vector3.Cross(freeAxis, Vector3.Right); } } Limit.TestAxis = baseAxis; Motor.TestAxis = baseAxis; Add(BallSocketJoint); Add(AngularJoint); Add(Limit); Add(Motor); }
MarsRoverMovement roverMovement = new MarsRoverMovement(); // creates the aspects of the rovers movement #endregion Fields #region Constructors public MarsRover() : base() { laserShot = Game1.Instance.Content.Load<SoundEffect>("lasershot"); explosionSound = Game1.Instance.Content.Load<SoundEffect>("explosion-01"); cameraArm = new BepuEntity(); drillArm = new BepuEntity(); //construct mars rover ase body roverBase = marsRoverBody.AddBox(new Vector3(260, 45, -260)); //create arms to hold both drill and camera/laser drillArm = marsRoverBody.AddCylinder("cylinder", new Vector3(267, 44, -244), false); cameraArm = marsRoverBody.AddCylinder("cylinder", new Vector3(254, 54, -252), true); //Create joint between rover body and drill arm roverMovement.CreateRevoluteJoint(out roverMovement.bodyDrillJoint, roverBase, drillArm, new Vector3(267, 44, -250), 3500, Vector3.Right); roverMovement.roverJoints.Add(roverMovement.bodyDrillJoint); //Create joint between rover body and camera/laser arm roverMovement.CreateRevoluteJoint(out roverMovement.bodyCameraCylinderJoint, roverBase, cameraArm, cameraArm.body.Position, 1500, Vector3.Up); roverMovement.roverJoints.Add(roverMovement.bodyCameraCylinderJoint); //create container for camera/laser cameraLaserContainer = marsRoverBody.AddCylinder("cube", new Vector3(254, 61, -252), true); //Create joint between camera/laser arm and container for camera/laser roverMovement.CreateRevoluteJoint(out roverMovement.cameraLaserContainerXaxisRotation, cameraArm, cameraLaserContainer, cameraLaserContainer.body.Position, 2500, -Vector3.Right); roverMovement.roverJoints.Add(roverMovement.cameraLaserContainerXaxisRotation); //create the four back wheels of the rover and connect them to the body Entity backWheel1 = marsRoverBody.AddWheel(new Vector3(250, 42, -267), roverBase.body); roverMovement.ConnectWheelBody(backWheel1, roverBase); Entity backWheel2 = marsRoverBody.AddWheel(new Vector3(270, 42, -267), roverBase.body); roverMovement.ConnectWheelBody(backWheel2, roverBase); Entity backWheel3 = marsRoverBody.AddWheel(new Vector3(250, 42, -260), roverBase.body); roverMovement.ConnectWheelBody(backWheel3, roverBase); Entity backWheel4 = marsRoverBody.AddWheel(new Vector3(270, 42, -260), roverBase.body); roverMovement.ConnectWheelBody(backWheel4, roverBase); //Create the two driving wheels and connect them to the body var wheel1 = marsRoverBody.AddWheel(new Vector3(270, 42, -255), roverBase.body); roverMovement.SetUpFrontMotorWheels(roverBase, wheel1, out roverMovement.drivingMotor1, out roverMovement.steeringMotor1); var wheel2 = marsRoverBody.AddWheel(new Vector3(250, 42, -255), roverBase.body); roverMovement.SetUpFrontMotorWheels(roverBase, wheel2, out roverMovement.drivingMotor2, out roverMovement.steeringMotor2); var steeringStabilizer = new RevoluteAngularJoint(wheel1, wheel2, Vector3.Right); Game1.Instance.Space.Add(steeringStabilizer); }
/// <summary> /// Constructs a new constraint which restricts two 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="lineAnchor">Location of the anchor for the line to be attached to connectionA in world space.</param> /// <param name="lineDirection">Axis in world space to be attached to connectionA along which connectionB can move and rotate.</param> /// <param name="pointAnchor">Location of the anchor for the point to be attached to connectionB in world space.</param> public LineSliderJoint(Entity connectionA, Entity connectionB, Vector3 lineAnchor, Vector3 lineDirection, Vector3 pointAnchor) { if (connectionA == null) connectionA = TwoEntityConstraint.WorldEntity; if (connectionB == null) connectionB = TwoEntityConstraint.WorldEntity; PointOnLineJoint = new PointOnLineJoint(connectionA, connectionB, lineAnchor, lineDirection, pointAnchor); AngularJoint = new RevoluteAngularJoint(connectionA, connectionB, lineDirection); Limit = new LinearAxisLimit(connectionA, connectionB, lineAnchor, pointAnchor, lineDirection, 0, 0); Motor = new LinearAxisMotor(connectionA, connectionB, lineAnchor, pointAnchor, lineDirection); Limit.IsActive = false; Motor.IsActive = false; Add(PointOnLineJoint); Add(AngularJoint); Add(Limit); Add(Motor); }
/// <summary> /// Constructs a new demo. /// </summary> /// <param name="game">Game owning this demo.</param> public ReverseTrikeDemo(DemosGame game) : base(game) { game.Camera.Position = new Vector3(0, 2, 15); Space.Add(new Box(new Vector3(0, -5, 0), 20, 1, 20)); var body = new Box(new Vector3(0, 0, 0), 2, 1, 3, 10); body.CollisionInformation.LocalPosition = new Vector3(0, .8f, 0); Space.Add(body); #region First Wheel var wheel = new Cylinder(body.Position + new Vector3(-1.3f, 0, -1.5f), .2f, .5f, 4); wheel.Material = new Material(1.5f, 1.5f, 0); wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2); //Preventing the occasional pointless collision pair can speed things up. CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase); //Connect the wheel to the body. var ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position); var swivelHingeAngularJoint = new SwivelHingeAngularJoint(body, wheel, Vector3.Up, Vector3.Right); //Motorize the wheel. drivingMotor1 = new RevoluteMotor(body, wheel, Vector3.Left); drivingMotor1.Settings.VelocityMotor.Softness = .2f; //Let it roll when the user isn't giving specific commands. drivingMotor1.IsActive = false; steeringMotor1 = new RevoluteMotor(body, wheel, Vector3.Up); steeringMotor1.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. steeringMotor1.Basis.SetWorldAxes(Vector3.Up, Vector3.Right); steeringMotor1.TestAxis = Vector3.Right; //Add the wheel and connection to the space. Space.Add(wheel); Space.Add(ballSocketJoint); Space.Add(swivelHingeAngularJoint); Space.Add(drivingMotor1); Space.Add(steeringMotor1); #endregion #region Second Wheel wheel = new Cylinder(body.Position + new Vector3(1.3f, 0, -1.5f), .2f, .5f, 4); wheel.Material = new Material(1.5f, 1.5f, 0); wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2); //Preventing the occasional pointless collision pair can speed things up. CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase); //Connect the wheel to the body. ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position); swivelHingeAngularJoint = new SwivelHingeAngularJoint(body, wheel, Vector3.Up, Vector3.Right); //Motorize the wheel. drivingMotor2 = new RevoluteMotor(body, wheel, Vector3.Left); drivingMotor2.Settings.VelocityMotor.Softness = .2f; //Let it roll when the user isn't giving specific commands. drivingMotor2.IsActive = false; steeringMotor2 = new RevoluteMotor(body, wheel, Vector3.Up); steeringMotor2.Settings.Mode = MotorMode.Servomechanism; //Configure the motor. See wheel 1 for more description. steeringMotor2.Basis.SetWorldAxes(Vector3.Up, Vector3.Right); steeringMotor2.TestAxis = Vector3.Right; //Add the wheel and connection to the space. Space.Add(wheel); Space.Add(ballSocketJoint); Space.Add(swivelHingeAngularJoint); Space.Add(drivingMotor2); Space.Add(steeringMotor2); #endregion #region Third Wheel wheel = new Cylinder(body.Position + new Vector3(0, -.3f, 1.5f), .2f, .5f, 4); wheel.Material = new Material(1.5f, 1.5f, 0); wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2); //Preventing the occasional pointless collision pair can speed things up. CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase); //Connect the wheel to the body. ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position); //Notice that the third wheel isn't a swivel hinge, it's just a revolute axis. //This lets it roll, but prevents flopping around like the wheels of a grocery cart. //Could have used a RevoluteJoint solver group here, but this shows it's possible to do //the same things without using the combo-constraints. var revoluteAngularJoint = new RevoluteAngularJoint(body, wheel, Vector3.Right); //Add the wheel and connection to the space. Space.Add(wheel); Space.Add(ballSocketJoint); Space.Add(revoluteAngularJoint); #endregion int xLength = 180; int zLength = 180; float xSpacing = 8f; float zSpacing = 8f; var heights = new float[xLength, zLength]; for (int i = 0; i < xLength; i++) { for (int j = 0; j < zLength; j++) { float x = i - xLength / 2; float z = j - zLength / 2; //heights[i,j] = (float)(x * y / 1000f); heights[i, j] = (float)(10 * (Math.Sin(x / 8) + Math.Sin(z / 8))); //heights[i,j] = 3 * (float)Math.Sin(x * y / 100f); //heights[i,j] = (x * x * x * y - y * y * y * x) / 1000f; } } //Create the terrain. var terrain = new Terrain(heights, new AffineTransform( new Vector3(xSpacing, 1, zSpacing), Quaternion.Identity, new Vector3(-xLength * xSpacing / 2, -10, -zLength * zSpacing / 2))); Space.Add(terrain); game.ModelDrawer.Add(terrain); }
void AddBackWheel(Vector3 wheelOffset, Entity body) { 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 revoluteAngularJoint = new RevoluteAngularJoint(body, wheel, Vector3.Right); //Add the wheel and connection to the space. Space.Add(wheel); Space.Add(pointOnLineJoint); Space.Add(suspensionLimit); Space.Add(suspensionSpring); Space.Add(revoluteAngularJoint); }
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); }
public TreadSegment(Vector3 segmentPosition, Entity body, TreadSegmentDescription treadSegmentDescription) { Entity = new Cylinder(segmentPosition, treadSegmentDescription.Width, treadSegmentDescription.Radius, treadSegmentDescription.Mass); Entity.Material.KineticFriction = treadSegmentDescription.Friction; Entity.Material.StaticFriction = treadSegmentDescription.Friction; Entity.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2); //Preventing the occasional pointless collision pair can speed things up. CollisionRules.AddRule(Entity, body, CollisionRule.NoBroadPhase); //Connect the wheel to the body. SuspensionAxisJoint = new PointOnLineJoint(body, Entity, Entity.Position, Vector3.Down, Entity.Position); SuspensionLengthLimit = new LinearAxisLimit(body, Entity, Entity.Position, Entity.Position, Vector3.Down, -treadSegmentDescription.SuspensionLength, 0); //This linear axis motor will give the suspension its springiness by pushing the wheels outward. SuspensionSpring = new LinearAxisMotor(body, Entity, Entity.Position, Entity.Position, Vector3.Down); SuspensionSpring.Settings.Mode = MotorMode.Servomechanism; SuspensionSpring.Settings.Servo.Goal = 0; SuspensionSpring.Settings.Servo.SpringSettings.Stiffness = treadSegmentDescription.SuspensionStiffness; SuspensionSpring.Settings.Servo.SpringSettings.Damping = treadSegmentDescription.SuspensionDamping; SuspensionAngularJoint = new RevoluteAngularJoint(body, Entity, Vector3.Right); //Make the joint extremely rigid. There are going to be extreme conditions when the wheels get up to speed; //we don't want the forces involved to torque the wheel off the frame! SuspensionAngularJoint.SpringSettings.Damping *= Entity.Mass * 50; SuspensionAngularJoint.SpringSettings.Stiffness *= Entity.Mass * 50; //Motorize the wheel. Motor = new RevoluteMotor(body, Entity, Vector3.Left); Motor.Settings.VelocityMotor.Softness = treadSegmentDescription.MotorSoftness; Motor.Settings.MaximumForce = treadSegmentDescription.MotorMaximumForce; }