More info here
Lightwave 11.6 python script for creating a custom box shape with a non-modal interface. It will show in the Object Properties, Add Custom Object list as "Python Box Shape". The same settings can be manually copied to the make cube geometry tool to get permanent geometry.
works with LW2018
right click the link above to download
To install copy the box_shape.py file to the python script plugin folder, something like:
"C:\Program Files\NewTek\LightWave11.6\support\plugins\scripts\Python\"
April 21 2014: v 1.1 dialog settings save with the scene