All right, took some time to actually integrate btGeneric6DofConstraint from test code to Urho3D::Constraint class. Currently, its use is similar to using the
btGeneric6DofConstraint(btRigidBody& rbB, const btTransform& frameInB, bool useLinearReferenceFrameB);
constructor for the caller. But to get around the multiple axis constraint issue when using btGeneric6DofConstraint class, the 2nd btRigidBody is not static but dynamically created (opaque to the caller) because its rotation is manipulated at runtime to overcome the axis constraint issue. And current implementation only deals with angular limit.
Anyway, I can create a repo for the integrated Urho3D::Constraint with this addition. Unfortunately, I cannot post the flyer code since it’s based on Unity - it’s free to use but I believe there’s restriction on posting it as open-source code.
Let me know if anyone is interested in seeing a repo for this.