overlaying info (2d on 3d most likely)

If the variable has changed by the time renderworld is called then use another variable to keep track of it at the point you desire and text out that instead.

EDIT: By the way, I'm having a bit of trouble understanding how this problem is arising for you in this particular context - a model is always going to be where it is at the point of rendering; so just render, text-out the values you need (and you could interrogate the object directly if needed... text x,y,entityx(myObject)) then flip.