but that's the issue I have currently, GP floats 1 meter over the apron.
Yes, I should have realized that, but I failed to appreciate I was dealing with two users with different issues, one with runways, one with aprons.
Nonetheless, the answer is the same. If the GP is wholly on the apron, it should be displayed at apron elevation.. But, in your case, Roland, it appears the terrain elevation computed by PV5 (the elevation at which a GP is displayed) is not apron elevation. What you suggest may (and I stress may) solve your specific issue. But, if you have numerous aprons in a sloping airport, I doubt that the PV5 internally computed terrain elevation is the same for all aprons - which it appears PV5 places at ARP elevation regardless. And it certainly wouldn't work for GPs on runways or taxiways - even level ones - where such an offset would bury the GP.
But, "I feel your pain". For a permanent solution, LM will have to fix PV5 so that ground polys are "on the ground". Then, if changes to ADE-GP are required, I'll do my best to comply. In the meantime, I've created a development release of ADE-GP that will allow you to "fix" individual GPs for horizontal areas. Previous releases of ADE-GP deleted the GP .mdl files it creates since they can consume a lot of disk space. However, ADE-GP
Development Release 2.2.23.3, available from
http://stuff4fs.com, leaves that folder intact when compiling for PV5, thus allowing you to modify the _GP.bgl file.
To do so, compile your GPs normally. Then, locate the file ADE-GP.xml in the ADE folder. Edit the elevation parameter of the XML segments that pertain to the GPs of interest and save the .xml file back into your ADE folder. Open the PV5 SDK folder World\Scenery and you will see
bglcomp.exe. Drag the icon of the .xml file over bglcomp.exe. After a slight delay, an updated
ADE-GP.bgl will appear in your ADE folder. Rename that file as necessary and copy it to the relevant \scenery folder.
Please do not ask for assistance in this regard.