OOF: Finite Element Analysis of Microstructures
Before a mesh is modified in any way, a copy of the mesh is stored in a stack. The commands in this menu allow you to move from mesh to mesh in the stack. This allows you to undo changes, or to flip back and forth between old and new meshes to decide which ones you prefer. If any mesh-modifying command is executed when you are not at the top of the stack, the meshes at the top of the stack will be lost.
Because meshes can take up quite a bit of memory, the stack isn't unlimited, as it is for pixel selections. If the stack fills up, the oldest meshes will be lost. Furthermore, copying meshes takes some time, so for with very large systems you may want to set the stack size to zero.