8 hours ago
An easy way to do this is to make selections (with the selection tools) of walls, windows, doors, etc. and convert them to paths, so that the selections are preserved (Gimp menu: Select / To Path). Save your work as a Gimp .xcf file, so that your work is not lost. To color, convert the paths to selections and fill them with a color (Gimp menu: Select / Selection from Paths). Check out this site to see how they use selections to fill selections.
https://www.visualizecolor.com/ppgpaints...c69991947f
https://www.visualizecolor.com/ppgpaints...c69991947f