I do quite a bit of illustrations in Adobe Illustrator where I first turn a photo of the original pencil/ink drawing into a template. This make the illustration lighter and locks it. Then in separate layers above the original, I start building the illustration.
The same can be done with this as well I also try to name my layers when I go along, if I need to refer to parts of an image later. I do not do this in all images though, just ones where I might need to find pieces of the illustration to work on. For this, naming the layers will be helpful to you if you want change something later. Here you can see some of my process for turning an illustration into a graphic. Granted this is a Maneki-Neko cat... not a layout for a house. But the same principles apply for the beginning steps. https://www.behance.net/videos/247cdb31-8e2f-4fc3-b482-a8d84f402d3b/1st-Follower-Design-Challenge-Maneki-Neko-FREE-ASSETS-AFTER-THE-STREAM Note I did not really name the layers of this illustration, but I always do for more complex illustrations.... organization is key and helps you in the long run.
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