From BlenderWiki

[edit] Modifiers and deformation

Modifiers are automatic operations that affect an object in a non-destructive way. With modifiers, you can perform many effects automatically that would be otherwise tedious to do manually (such as subdivision surfaces) and without affecting the base topology of your object. Modifiers work by changing how an object is displayed and rendered, but not the actual object geometry. You can Apply a modifier if you wish to make its changes permanent.

There are two types of modifiers:

• Deform modifiers

Deform modifiers only change the shape of an object, and are available for Mesh, Text, Curve, Surface and Lattice objects.

• Constructive modifiers

Constructive modifiers are only available for Mesh objects, and typically change mesh topology in some way (e.g. the subsurf modifier which performs Catmull-Clarke subdivision).

[edit] Interface

The interface that is used for modifiers and constraints is described here:

• Modifier Stack

[edit] Modifiers

Modifiers are added from the Modifiers tab in the Editing context (F9). The Modifiers tab appears when a Mesh, Curve, Surface, Text, or Lattice Object is added or selected.

• Armature - Use bones to deform and animate your mesh.
• Array - Create an array out of your basic mesh and similar (repeating) shapes.
• Bevel - Create a bevel on a selected mesh/object.
• Booleans - Combine/subtract/intersect your mesh with another one.
• Build - Assemble your mesh step by step when animating.
• Cast - Shift the shape of a mesh, surface or lattice to an sphere, cylinder or cuboid.
• Cloth - Simulate the properties of a piece of cloth. It is inserted in the modifier stack when you designate a mesh as Cloth.
• Curve - Bend your mesh using a curve as guide.
• Decimate - Reduce the polygon count of your mesh.
• Displace - Use textures or objects to displace your mesh.
• EdgeSplit - Add sharp edges to your mesh.
• Explode - Splits apart a mesh when, used with particles.
• Hooks - Add a hook to your vertice(s) to manipulate them from the outside.
• Lattice - Use a Lattice object to deform your mesh.
• Mask – Allows you to hide some parts of your mesh.
• Mesh Deform – Allows you to deform your mesh by modifying the shape of another one, used as a "Mesh Deform Cage" (like when using a lattice).
• Mirror - Mirror an object about one of its own axis, so that the resultant mesh is symmetrical, and you only have to model/edit half or a fourth of it.
• Particle Instance - Make an object act similar to a particle but using the mesh shape instead.
• Smooth - Smooth a mesh by flattening the angles between its faces.
• Softbody – The object is soft, elasticated... Modifier added when you designate a mesh as Softbody.
• SubSurf - Smooth the surface by creating interpolated geometry.
• UVProject - Project UV coordinates on your mesh.
• Wave - Deform your (dense) mesh to form an (animated) wave.

[edit] Subpages

1. Animation
2.    Build
3. Deform
4.    Armature
5.    Cast
6.    Curve
7.    Lattice
8.    Mesh Deform
9.    Wave
10. Mesh
11.    Bevel
12.    Booleans
13.    Decimate
14.    Displace
15.    EdgeSplit
16.    Explode
17.    Hooks
18.    Mask
19.    Mirror
20.    Smooth
21.    Subsurf
22. Objects
23.    Array
24.    Particle Instance
25. Textures
26.    UVProject
27. The Stack