Is it possible to fill a specific surface area, Like the photoshop paint bucket

I want to fill a random shaped area with a wheat field for a RTS game. This roads/outlines are made from splines.

Heres an example:

Is it possible to achieve such a thing in Unreal? Please let me know.
Thank You!

If you’re talking about foliage, the closest to that which I can think of is dragging one actor out onto the screen, then holding Alt and clicking and dragging the object to make a duplicate. Then, while holding Ctrl or Shift, click on the duplicate. With both actors selected, hold Alt then click and drag. (You can also duplicate by holding Alt and transforming or rotating.) Repeat this process, with more and more trees as needed.

Well this is for a RTS game so it has to be done at runtime sadly. I was thinking a simple texture overlay like a decal or something should be enough.