The actual render camera location that vorpX has access to is not necessarily the same as the one a game uses for collision detection etc. In some games that might be the case, in others it will not. Positional tracking in vorpX works great for peeking around corners, dodging, moving a step forward/backward and similar things, but not necessarily for freely roaming an entire 3x3m playspace. Hence the recommendation to stay more or less in place that you see when a game starts.