cross section elevation (seabed)

For hydrographic data, its elevation always defined as negative value such -3.5m, -10m....

During present into the drawing, hydrographic data must be display in positive value in dwg while z value of land survey required to swap into negative.

(* in terramodel, those negative z value import into the terramodel will become positive automatically in the screen but z value for each point stil remain negative, this very important for those seabed mapping industry.

my question is unlike terramodel, autocad display z elevation accordingly during import the xyz data. 

As per photo attached, right hand side is the one i requested. 

Manually edit negative sign to positive sign and the other hand might spend a lot of time if there are many multiple cross section view, omit the negative in original data might cause whole surface became up side down. any good suggestion or solution for me?

thanks.

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