Isn't IGA's shtick just replacing classical shape functions with the splines used to specify the geometry?
If I recall correctly convergence rates are exactly the same, but the whole approach fails to realize that, other than boundaries, geometry and the fields of quantities of interest do not have the same spatial distributions.
IGA has been around for ages, and never materialized beyond the "let's reuse the CAD functions" trick, which ends up making the problem more complex without any tangible return when compared with plain old P-refinent. What is left in terms of potential?
> Tom Hughes, who is mentioned several times, is now the de facto leader of the IGA research community.
I recall the name Tom Hughes. I have his FEM book and he's been for years (decades) the only one pushing the concept. The reason being that the whole computational mechanics community looked at it,found it interesting, but ultimately wasn't worth the trouble. There are far more interesting and promising ideas in FEM than using splines to build elements.