Feature Request: Draw "not difficult terrain"

[TogaParty]

Is your feature request related to a problem? Please describe.
I would like to be able to set a scene to difficult terrain, then draw the "normal" terrain instead of the inverse. e.g. I have a jagged island scene where most of it is difficult, with islands of normal terrain. This is cumbersome and very time consuming to build by defining difficult terrain, wherein the water is the difficult terrain. I would include an image, but I don't know how to do that in github.

Describe the solution you'd like
Scene settings for default terrain that could be set to difficult (x2), drawing tools could be used to define "normal" terrain (x1)
A clear and concise description of what you want to happen.

Additional context
Add any other context or screenshots about the feature request here.