Subdivision is a method of refining the control mesh and making the surfaces smoother. In subdivision, new vertices are added to create a more complex and finer mesh.

Setting a resolution is a method of creating a finer and complex virtual control mesh for manipulation. When a shape has high resolution, you can transform, scale, or planarize the mesh. However, you cannot create new vertices which limits the use of other Freestyle commands.

You can set resolution at the following three levels:

The number in the icon indicates the highest resolution level at which the mesh changes are made to the shape.

As the resolution level increases, the mesh density increases, and the shape becomes smoother. New vertices appear in the virtual mesh. When you exit Resolution mode, the virtual mesh disappears. Although, the control mesh remains unchanged, the changes that you make to a shape in Resolution mode are permanent, unless you reset those changes.

You can reset, suppress, or resume specific modifications done on the selected elements at the active resolution level.

You can also reset, suppress, or resume all modifications done at any resolution level, without activating that resolution level.

In Subdivision, you subdivide the shape for a finer and complex control mesh. In Resolution mode, the control mesh does not change. However, when you set a resolution level, new vertices are created, and a virtual control mesh appears. If you exit Resolution mode without resetting changes made in Resolution mode, the following occurs:

Therefore, you can transform or scale the virtual control mesh created in Resolution mode without losing changes made in Resolution mode. If you do perform an operation that results in the addition of new vertices, then you might lose changes made in Resolution mode.