I've been recommended to instal Mask Tools add-on.
However in the Github link, I don't see the button to download a Zip file?
Would you mind telling me how to install this addon? Shoul I donwload every py file and compress them in my machine so I can install via preferences?
https://github.com/bookyakuno/-Blender-/tree/master/maskTools_2-8
Thank you.
Whoever recommended this should tell you how, but this Addon hasn't seen any development in over a year and the Blender Python API has changed in that time, so it might not even work any more.
Furthermore Blender has grown, so maybe (part of) the functionality is already in Blender now...
Tried the README, but I don't know any Japanese