  In this article, we revisited Ba\v{z}ant's comments on the implementation of
hyperelastic material models in commercial finite element software. We would
like to clarify that our assertions only apply if the material models are
implemented as hypoelastic, i.e. by incremental stress updates, in common
interfaces (including, in particular, umat in Abaqus). This assumption was not
made sufficiently clear in the article.
  If, on the other hand, the stress calculations are implemented using the umat
interface with absolute (or "total") stress updates, as is also assumed in the
uhyper interface, there is no difference in the internal processes or the
results between the umat and the uhyper implementation. This applies to highly
compressible formulations as well, where the Kirchhoff and Cauchy stress
tensors are clearly distinguished.
