I need to move the box2d body according to position received form game center server.
After receiving position I just update the body position using: -
Carbody->SetTransform(b2Vec2(serverposition.x,serverposition.y),0);
But its moving the body inapprotiate manner (for example. Body is showing somewere lese in the screen). At same time my sprite image not moving (attached with body).
What i did to solve the positioning problem is i taken a normal sprite image and just change position in update with that box2d body position.
Eg:-
your carbody movement based on server position. it will move invisibly. your b2body without userdata(image)
carMainBody->SetTransform(b2Vec2(serverposition,carMainBody->GetPosition().y), 0.0f);
here your normal sprite image. just attch your sprite image like this
car->setPosition(ccp(carMainBody->GetPosition().x*PTM_RATIO,carMainBody->GetPosition().y*PTM_RATIO));
This method worked fine for me.