Imagine we have a simple 2D FEM solver (we are dealing with solid mechanics) and we would like to develop it to a 3D FEM solver (let's say for the same solid mechanics problem) in this case what are the inevitable changes/modifications to be made in the code?
I understand that some might answer "It depends on the type of the problem and it is different from case to case", but I am curious to know if there is any generic standard procedure for such transformation that should inevitably be considered regardless of the type of the problem?
I am of course talking about the places in the code where I should implement the modifications.
If you need a more specific presentation of the problem, here is the 2D code I am willing to develop to 3D. To see the code please click on this link