Now it was time for Photoshop. The texture is quite simple: it's just the photo with some details. I added some graffiti and some dirt. For example, the monkey is graffiti, which I put in with Darken blend mode. When making textures you need to play a lot with blending modes, the opacity of the layer, levels, etc. I followed the same process for the other building (Fig.11).
I used a different trick for the windows. I made a black and white texture, which you can see. After that, I began the setup of the shader. I find it more comfortable to use the Material Editor. In my opinion, it's easier to see and understand what you are doing. In this case, I had a base material, which had a falloff material in the reflection slot. Then I used a VRayBlendMtl, which is a material that allows you to use masks and mix two different materials. I used the texture that I made as a mask and as a material (Fig.12).
I used the same technique for the car shader; the only difference was that the base material was VRayCarPaintMtl and the coat material was a simple material with a dark color. I also added a UVW map with Planar projection to place the mask in the correct position (Fig.13).
Fig.14 shows the setup of the shader. I also added a texture in the bump map slot. With the UVW Planar projection I could place it correctly.
I was now ready to render all the elements and composite them in Photoshop. The raw render can be seen in Fig.15.