# What is the difference between a subdivision surface modifier and multiresolution modifier?

I'm currently modeling my game character in Blender (see below picture).

What is the difference between a subdivision surface modifier and a multiresolution modifier? I know they smooth the surface but are there specific characteristics to using each and what are those?

When using the sculpt tool, you will sometimes want to add more detail than your mesh has vertices to support. You could add vertices by subdividing the mesh, but subdividing the mesh will increase the complexity of the model, slowing blender down, making the model larger, making the mesh less usable for certain applications (like games).

Sub surface allows you to increase the vertices as a modify, but isn't affected by sculpting. It's purpose is to add geometry to the whole mesh and make a lower poly figure a higher quality without increasing the complexity of the mesh. You cannot move, alter or sculpt the new vertices without applying the subsurface. It wasn't designed for it.

Multi resolution modifier was added to allow you to add geometry for the purposes of adding detail to a sculpt. Vertices in a multi res modifier are affected by a sculpt even when not applied. This allows you to sculpt with more verts than the base mesh has. This is useful because you sculpt at a higher resolution, bake out the sculpt as a map, and apply it to the mesh as a normal map, without increasing the actual number of vertices the mesh has.

So, if you're not sculpting, sub surface and multi resolution are logically equivalent, and the preference is for sub surface (less data in memory, easier interface). If you are sculpting, and want to keep the mesh low poly, but need more detail in the sculpt, use multi resolution and then bake out the normal map (which can then be applied to the surface of the object as a texture in the cycles node editor).

• I appreciate the clarity in your response. Very easy to follow, thank you. – John H Apr 26 '14 at 1:29
• This was a really helpful solution for me! It should be accepted as a solution. – babaliaris Jun 11 '19 at 23:59

From the wiki:

Another way to subdivide is with the MultiResolution Modifier. This differs from Subsurf in that MultiRes allows you to edit the mesh at several subdivision levels without losing information at the other levels. It is slightly more complicated to use, but more powerful.

In other words:
Changes made to the mesh (via sculpting) will be applied to lower and higher subdivision levels as well as the current level. To apply changes to the base mesh you must press Apply Base on the modifier.

This is different from the subserf modifier, where the subdivided mesh cannot be edited unless the modifier is applied.

## Baking:

Another advantage of the multires modifier (in certain cases, of course) is the normal map baking workflow:

1. Model low poly mesh (in this case a cube) and UV unwrap (you can UV unwrap later too)

Note that you can also bake normals to the base mesh if the preview level is 0.