/// <summary>Create this fixture in the simulation</summary>
public virtual void Initialise(LPBody bod)
{
body = bod;
myIndex = body.AddFixture(this);
GetPhysProps();
IntPtr shape = GetShape();
ThingPtr = LPAPIFixture.AddFixture(body.GetPtr(), (int)Shapetype
, shape
, Density, actualFriction, actualRestitution, IsSensor, myIndex);
LPAPIFixture.SetFixtureFilterData(ThingPtr, (Int16)CollisionGroupIndex, categoryBits, maskBits);
}