Currently when geometry is created, Creo does not add the surfaces as sematic references to the dimensions that control that geometry. Per PTC:
The Product Manager confirmed that this has been requested by customers before. It has been explored as an option to include but the decision has been made not to add. For simple geometry such as a block, it is easy to identify the correct surfaces, but as sketches become more complex, the automatic addition is not as robust. So rather than adding wrong or unneeded references which would need to be removed, you will need to manually add the references.
This idea is to change the behavior so that simple geometry (ie blocks) for which it is easy to add sematic references to go ahead and do so. Certainly for us and I suspect for the larger community there is more blocky geometry than not and auto adding these surfaces would save time.
