This is a big task for someone new to Archicad and GDL.
Is that Bautech add-on not suitable for your needs?
It will save you re-inventing the wheel all over again.
Or can you look at the code for that object to learn from it - so long as it has not bee hidden or password protected then you will be able to open the scripts.
There are other cladding add-ons - one that I can think of is by James Hardie - but not sure if this is just for Australian users or not.
http://www.accel.com.au/cad_hardicontent.php#hcont2
Your GDL object will need to have the subtype of "wall accessory" so it will work with the wall accessory add-on - otherwise it is just an object and will not be associated to a wall.
Then you will need to retreive all the wall/opening dimensions and probably uses arrays to set out the panels.
This is where you will want to study existing wall accessory objects.
There are some in the default Archicad library you will be able to open.
Barry.
One of the forum moderators.
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