Here is a link to a post that has a 'tentmaker' object - basically a shade sail.
This is a very old object but I think it is the one I still have in my library.
Hopefully it can help.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10