  The novel STEVE (i.e., Space-Time-Enclosing Volume Extraction) algorithm is
described here for the very first time. It generates iso-valued hypersurfaces
that may be implicitly contained in four-dimensional (4D) data sets, such as
temporal sequences of three-dimensional images from time-varying computed
tomography. Any final hypersurface that will be generated by STEVE is
guaranteed to be free from accidental rifts, i.e., it always fully encloses a
region in the 4D space under consideration. Furthermore, the information of the
interior/exterior of the enclosed regions is propagated to each one of the
tetrahedrons, which are embedded into 4D and which in their union represent the
final, iso-valued hypersurface(s). STEVE is usually executed in a purely
data-driven mode, and it uses lesser computational resources than other
techniques that also generate simplex-based manifolds of codimension 1.
