An important aspect of each modifier is that you will lose any effects it
produces once you remove them from any object. If you want to make
the effects permanent, use the "Apply" option available in each modifier.
After using that option, the modifier disappears from the list, and the
modification becomes part of the object.
That is useful when you have a project where you must create an object
based on multiple modifiers, which you can also use as a reference to
start modeling. For instance, it is possible to add a Mirror Modifier and
make it a permanent part of a 3D model.
Tip: Before applying a modifier's effects, you should make a backup
copy of your 3D model and place it to a different Collection. By hiding
that Collection, you keep an untouched version of any 3D model with all
modifiers.
4.2 Subdivision Surface modifier
One of the most used modifiers for modeling is the Subdivision Surface,
which smoothes your 3D models by adding lots of new faces to the
selected polygon. The modifier is one of the primary tools for techniques
such as mesh modeling.
A popular workflow for many modeling projects is to start with a low poly
version of an object, and later apply a modification to increase polygon
count. By adding more polygons, it is also possible to smooth existing
surfaces.
Figure 4.4 shows an example of the results of a Subdivision Surface
Modifier (High Poly).