3D crack modeling using CTMOPT macro in ANSYS

Hello Everybody..

I am MS student in University of cincinnati, Oh, USA. I am working on
fractures in thin film and for  that i need to model 3D cracks. Problem
is i cant just use extrude comand becuase, crack is not throughout tht
length of the film ( So i cant use th eapproch mentioned above). there
is CTMOPT macro in ansys which allows to desgin meshing at the crack
tip. I am struggling with the ewxplanation given there. If anybody has
detail information in how to implelment this macro, please let me
know. 

Thanknig you,

Sagar Bhamare