When Poser loads a prop into the document in the normal way (i.e. not a smart prop, and not loaded from a cr2) it adds an underscore and number to the props name. The number is incremented for each new instance of the prop that is loaded. prop square_1 prop square_2 prop square_3 prop square_4 Thus it seems that the name of the prop depends on the order it was loaded. I'm not quite sure how numbering is handled in the case of Smart Props, but I suspect this numbering issue might be involved in your problem.