New package for adding loads?

[ahojukka5]

Should we consider building a separate package for adding loads to continuum models? We could then have several problems, like

traction = Problem(Traction, "trac", 3)
pressureLoad = Problem(PressureLoad, "pressure load", 3)
volumeLoad = Problem(VolumeLoad, "volume load", 3)

and so on?

[ahojukka5]

Or maybe it's enough to have SurfaceLoad and VolumeLoad, we can then set fields to them and maybe add some helpers:

pressureLoad = PressureLoad(100.0)

and so on.