Adapt ViewField to be able to plot magnetic fields.

5 jobs for bfield in 5 minutes and 7 seconds (queued for 8 seconds)
Status Name Job ID Coverage
  Build
passed build-centos7 #17099117

00:04:00

passed build-centos7-view97 #17099118

00:05:07

passed build-fedora32 #17099120

00:03:58

passed build-fedora33 #17099121

00:04:20

passed build-ubuntu #17099119

00:04:26