A mesh torus has two radius values. One value defines the tube. The other value defines
the path, which is equivalent to the distance from the center of the torus to the
center of the tube. By default, a torus is drawn parallel to and is bisected by the
XY plane of the current UCS.

A mesh torus can be self-intersecting. A self-intersecting mesh torus has no center
hole because the radius of the tube is greater than the radius of the torus.

You can also use the Mesh Primitive Options dialog box to set the default number of
divisions for a mesh torus.

After a mesh primitive is created, the current level of smoothness for the object
can be modified.

Torus Creation Options

The Torus option of the MESH command provides several methods for determining the
size and rotation of the mesh tori you create.

• Set the size and plane of the circumference or radius. Use the 3P (Three Points) option to define the size of the mesh torus anywhere in
  3D space. The three points also define the plane of the circumference. Use this option
  to rotate the mesh torus as you create it.
• Set the circumference or radius. Use the 2P (Two Points) option to define the size of the mesh torus anywhere in 3D
  space. The plane of the circumference matches the Z value of the first point.
• Set the location to be tangent to two objects. Use the Ttr (Tangent, Tangent, Radius) option to define points on two objects. Depending
  on the specified radius distance, the path of the torus is located as near as possible
  to the tangent points you specify. You can set up tangency with circles, arcs, lines,
  and some 3D objects. The tangency points are projected onto the current UCS. The appearance
  of tangency is affected by the current level of smoothness.