A lattice is a structure of points for carrying out free-form deformations on any deformable object. To create deformation effects, you edit the lattice by moving, rotating, or scaling the lattice structure, or by directly manipulating the lattice points. In general, you create effects by editing any of the lattice deformer’s attributes.
A lattice deformer includes two lattices: an influence lattice and a base lattice. By itself, the term “lattice” typically refers to the influence lattice. You create deformation effects by editing or animating the influence lattice. The lattice deformer’s effect is based on any difference between the base lattice’s lattice points and the influence lattice’s lattice points. By default, the base lattice is hidden so that you can focus on manipulating the influence lattice. However, remember that the deformation effect depends on the relationship between the influence lattice and the base lattice.
Unique among deformer influence objects, lattices are themselves deformable objects. That means that you can create deformers that deform a lattice. For example, you can deform a lattice with a sculpt deformer, and the effect of the deformation on the lattice points will in turn deform the object the lattice is deforming. You can also assign deformation weights to lattice points by creating a cluster deformer for the lattice. Also, you can bind a lattice to a skeleton. When you move the skeleton, the lattice will deform with the action of the joints.