Subdivision models naturally have more polygons than realtime models because of holding edges and good edge flow overall. However, it’s important to realize that a really well-made subdivision model often has fewer polygons than a non-subdividable model.
The following two images show a model of a Dimplex grill. On the left is the original model an artist created. He tried to make the model so it didn’t need subdivision when used as a background or mid-range object. But the model had no holding edges, so it couldn’t be subdivided for close-ups. The model on the right, however, was made especially for subdivision, with fewer segments along the side. With no subdivision the model works for background shots, at Level 1 subdivision for mid-range shots, and Level 2-3 for closeups. The subdividable model, at the base level, has fewer polygons than the original model.
Original model. Too many segments and no holding edges.
Subdividable model. Fewer side segments, holding edges, fewer polygons overall.
Another example is this skull model. The original model (left) has a high number of polys. The same model can be represented with a much lower poly count (middle) with the option to subdivide (right). This gives the customer more options while keeping the base poly count fairly low for background use.
