@TwistedTwigleg said:
Well, this answer from the QA is a little old (pre Godot 3) but it probably will still work with some minor modifications. I’m not sure if you can save over a scene file already created though, but it does look like you can save scenes at runtime.
It's great, i think i found another way to make some sort of plugins.
You run a game scene with GUI panels and buttons to choose what tool to use on your models, for example select objects with mouse screen raycast , click another button to move and scale, or some other button to use some mesh splatter brush tool, once it's done you click on a save button to save your modified scene as a packed scene.
It should be an alternative and easy way to make tools because this is exactly the same as creating a game.