Cplane is an old and free plugin that gives LightWave users some of the functionality of a construction plane. It’s old, but thankfully it also has an LScript version that keeps it functional. The “one other thing” I forgot to mention in the video is that the .lsc version doesn’t work with multiple polygons selected. You’d be well advised to save your object before using this plugin because you can mess up the object’s orientation if you aren’t careful… of course, you could just undo, so I guess saving isn’t critical. I did have it crash the LW9.6 PPC Mac version of LW in my short testing, so saving isn’t a bad idea.