You can add triangles to a mesh model by creating nodes at any point in the graphics window. Although creating nodes using existing vertices or points on added geometric objects provides a framework for adding triangles, the ability to use any point in the graphics window to create a node offers increased flexibility in terms of triangle shape, direction and size.
For example:
and
, which are existing vertices:
, a point that does not lie on an existing vertex or object, to create the final node:
The new triangle is drawn: