So it's mid September and I've been exploring options for building the game environment.
I've been weighing up the alternatives of using 2D pictures versus using 3D models.
Both have pros and cons.
Both are possible.
I've been experimenting with creating 3D models in Sketchup, Blender and even Autodesk Inventor (because I'm familiar with this software for work).
I can create 3D model geometry fastest in Sketchup but unfortuately it doesn't properly handle texture mapping (UV wrapping). As a result when i bring the content into Unity the textures are not positioned or scaled correctly on the 3D models. For simple stuff like pavements it doesn't matter. However for other stuff it just fails.
I am a total novice to Blender and so I find creating 3D models to be very tedious.
It's quicker for me to create the 3D model in Sketchup and then import it into Blender.
From Blender I can UV unwrap the model to create a texture image that maps precisely to the model. I can either edit the UV image in GIMP or i can even directly paint on to the model in Blender -- although i found this to be unprecise and difficult.
The upshot of all this is that creating the environment - roads, pavements, shop-fronts, street furniture, bus stops, vehicles etc is going to be extremely tedious and slow if I create them all one by one as full 3D models.
Since i am a team of one, I am going to have to cheat a bit! So I shall do the interactive stuff as 3D - stuff like street furniture and pavement and bus stops. That way when the camera spins round 90 deg those items look correct to the camera.
However, creating shop-fronts etc is going to have to simply be done as cardboard cut-outs -- or rather quads with a carefully cropped and sized photo. To achieve a sense of 3D I will have to rely on parallax effects by placing small walls and fences in front of the bill-board shop fronts.
The video shows my environment scenary after one day of finding photos and editing them to suit.