It is done in the following way:
- determine the cavity for the new node
- start from the base element
- add elements one by one through adjacency; only element whose
circumcircle enclose the new node are taken into account
- check for nodes within the cavity; if any, remove the element to which
they belong from the cavity
- check that the cavity is convex in the sense that each cavity face is
visible from the new node, else the element bordering the face is removed
from the cavity
- remove the cavity elements
- create new elements connecting the new node with each of the cavity
faces
- if any element has a very small volume or at least one very small height
the original mesh of the cavity is restored
- since elements have been deleted and created the base element numbers of
the nodes still to be inserted may not be correct any more: perform a check
on these nodes and correct the base element numbers if necessary.
