f := zone.vol.deformed(z)

Get the volume of a zone using gridpoint positions that take into account accumulated gridpoint displacements.

This FISH intrinsic is meant to be used in a small-strain analysis when deformed zone volumes are required. This FISH intrinsic should not be used in a large-strain analysis (an incorrect volume will be returned). Use the intrinsic zone.vol in large-strain mode.

Returns:f - the zone volume adjusted for the current displacement field
Arguments:z - a zone pointer