Is there any other way to make a 2D city without the need to model 2D planes in a shape of buildings?
Well, you can make a 3D city, render it with transparent film and use it as 2D city…
This depends. If you have a still image you can obviously use a single image with a city on it.
If you have an animaton, you can get away with a single image if you have little camera movement and if this camera movement is horizontally. As soon as you have vertical pans and tilts a single image will usually not be enough.
If it’s just for a distant background, take a photograph of a city skyline, open it in Photoshop, select the sky/background and delete (so there is nothing there, no background layer etc.) Save with alpha/transparency and use as a texture in Blender with transparency. ‘Import Images as Planes’ addon in Blender may help here.
The harder part will be getting it to match the lighting of your scene.
haha heey maan now that’s what I call a solution