Once we had all the objects, we had to decide on where to place them. For that, you can either use a vector of the vehicle or pictures of the front, back and side. This is important to get the proportions of your layout correct.
The background was initially this dirty white texture, because it pictured R2 better than plain white. But because we really don't wash the bus so often, we figured it would get dirty by itself and ended up using a slight beige/creme-white instead. And if you think about it, R2 isn't particularly clean during a large part of the movies, so it get even more legit (what an excuse).
We decided the leg should come right above the rear wheel (the flat "fender" seemed like a perfect base), and up on the window so it would not look out of proportion, and because we wanted the amount of detail on it to show. Of course, it should also align with the gas cap.
What we needed to prepare at this stage was the bottom half (everything below the windows), which would be printed on vinyl. The second picture shows the file we sent for printing, with the modules already defined. Basically, we had a separated module for each door, one for whatever was left of the side, and one for the entire front.
If we were to do this again, we would choose to paint the background white and print each object as an individual sticker. The wrapping process can easily deform the vinyl, which is fine when applying a plain color, textured pattern, or even a landscape, but a nightmare when you have rectangular, round and square objects that look awful if distorted.
Also, there is a curved corner that connects the back and the side, where the tail light is located. It was a terrible idea to make a single module for this.