Plotting disp-x relative to the bottom

[Milads]

How do I define an extra variable in FLAC v9 so I can plot x‑displacement relative to the base of the model? In FLAC v8 I used something like:
ex_30($iev, $jev) = xdisp($iev, $jev) - xdisp($iev, 1)
What’s the equivalent way to set this up in FLAC v9? It seems like the zone.displacement-x is not a defined syntax in FISH

[jwang]

check this post, you can set this up similar:

Exporting Deformed Mesh

In large-strain mode, the gp positions have included displacements. In small-strain mode, we can run one-line FISH like [gp.extra(::gp.list,1) ::= gp.pos(::gp.list) + gp.disp(::gp.list)] then check FISH extra 1 for gridpoints.