A mesh is a collection of vertices, edges, (composed of a connection between two vertices), and faces (composed of 3 or more connected edges). Meshes are the most commonly used object type in Blender.
In Blender, meshes are collections of vertices, edges, and faces that are attached to an object. Mesh objects are one of the most widely used objects in Blender for many reasons, including:
- Ease of use. Mesh objects are easy to create and manipulate. Except for very high-resolution meshes, they don't take up a lot of memory or computational power, so they are quick to work with and make for small files.
- Modifiers. Modifiers can be applied to mesh objects, allowing for streamlined creation and manipulation of the meshes. For more information, see the modifiers tag.
- Physics simulations. Physics simulations often require a mesh object to work properly. This opens a whole new realm of realism and accuracy in physics-based simulations. For more information, see the physics tag.
- Portability. Meshes can be exported to all the major formats, including
Meshes can be edited in Edit Mode, which can be accessed by pressing Tab with a mesh object selected. For information on editing meshes, see the manual page on mesh editing.
Behind the scenes
A mesh, at its most basic form, contains three lists: a list of indexed vertices, a list of edges, and a list of polygons.
The list of vertices gives each vertex a number, starting at 0 and increasing by 1 for each vertex, and stores its position. For example, a vertex list might look like this:
- v0 = (0, 0, 0)
- v1 = (1, 0, 0)
- v2 = (1, 1, 0)
- v3 = (0, 1, 0)
These vertices represent the corners of a unit square on the XY-plane.
The list of edges does not store the positions of the two endpoints of each edge. Instead, it stores the indices of the two vertices that are the endpoints. This has the potential to save a significant amount of memory. For example, consider a vertex that has six edges attached to it. Instead of saving the coordinates six times over, the coordinates are saved once (in the vertex), and the edges only need the vertex number.
An edge list might look like this:
- e0 = (v0, v1)
- e1 = (v1, v2)
- e2 = (v2, v3)
- e3 = (v3, v0)
These edges connect the corners of the vertices in the right order to form a square. Note that no diagonal vertices, such as (v0, v2), are connected.
Finally, the polygon list is formed similarly to the edge list: each face is represented as a list of three or more vertices. Note that the order is important; a square and an hourglass have the same vertices, but they are connected in a different order.
Here is an example face list to complete our square:
- f0 = (v0, v1, v2, v3)
A face list for an hourglass would be as follows:
- f0 = (v0, v2, v1, v3)