firstly, I want to say sorry for any kind of mistakes regarding language and grammar (I’m obviously a nonnative speaker) and moreover I want to say sorry for being a bit of a noob (I’m just a student so definitely no kind of professional whatsoever). At the moment I want to make a project using the photo match feature and watched several tutorials for it. My problem: all of these projects used a picture taken from the ground of a building. However, my picture is taken from above the building. My goal is to be able to build something at the height of where the roof begins (so i want to replace the roof with a new one and add another floor to it). Can someone maybe just give me a short (and I really just need a short description - if you want to write more it’s also fine) description on how to do this in this case? As a first step I added in photoshop a parallel line of the front of the roof to the back as this building has a pitched roof. But still it wouldn’t help me to get the y-axis (referring to the model of the cartesian system on https://en.wikipedia.org/wiki/Coordinate_system as in my country the calling of the axises is different) right.
The origin of the coordinate system should be the left corner corner of the building (the one in the back of those two - I marked it with a green point on the image) and how i said i want to build something on top of the building replacing the original roof with a new one (and in the end I just want to take a screenshot of it from the perspective of the original photo).
I would really appreciate it if someone could help me a bit (maybe I’m just aligning the 4 red and green lines wrong - I don’t know to be honest but tried it several times).
Thanks in advance!
Edit: I just wanted to say that I have a basic understanding of SketchUp as I have used it for several projects (for example some woodwork) already. I just haven’t used the photo match feature.