public void AddBinaryForceComponent(BinaryForceComponent bfc)
 {
     bfc.BodyA.FGens.Add(bfc.ForceGenA);
     bfc.BodyB.FGens.Add(bfc.ForceGenB);
     bfcs.Add(bfc);
 }
 public void RemoveBinaryForceComponent(BinaryForceComponent bfc)
 {
     bfc.BodyA.FGens.Remove(bfc.ForceGenA);
     bfc.BodyB.FGens.Remove(bfc.ForceGenB);
     bfcs.Remove(bfc);
 }
 private void DrawSpring(BinaryForceComponent bfc)
 {
     var end1 = bfc.BodyA.Position + MathUtil.RotatePt(bfc.ConA, bfc.BodyA.Rotation);
     var end2 = bfc.BodyB.Position + MathUtil.RotatePt(bfc.ConB, bfc.BodyB.Rotation);
     GraphicsEngine.DrawLine(end1.P2C(), end2.P2C(), Color.Firebrick, 5);
 }