The rain was made with a very simple Pflow system with an emitter, gravity, wind and 3D sphere instance as a particle (Fig.11).
I used the speed of my sphere to create my rain with the help of V-Ray Motion Blur The result was very realistic, but it was a very slow process to render.
To increase the render speed I rendered three different passes of rain with 30k particles each, and I merged all my passes after in Photoshop (Fig.12).
The rain drops on the ground were made with a basic scatter with sprite and a rain drop alpha as the texture (Fig.13).
Finally the fog was a Z Depth inverted in Photoshop with a Level correction.
When I finished all my passes (Fig.14) I had just needed to import everything into Photoshop.
The matte was painted with some personal brushes and real pictures of buildings, which I relit so they corresponded to the scene. After this I sent all the renders to After Effects for the first color correction and to create all the lens flares.
I came back in Photoshop to finish the biggest part: adding all the VFX passes and painting the last details like the little rain drops, more detailed rain and the vapor where the water hit the objects (Fig.15 - 16). I then went back to After Effects to add filters such as blur, grain, etc.
Environments are not my specialty, but this was a very great experience. My wish to use Blade Runner as inspiration, and include so many details, was a good challenge. Creating this image also helped me to learn how to stay organized and many things about modeling, texturing and lighting. I was particularly surprised by Particle Flow, which I found to be a simple, but powerful tool. I hope my tips will help you (Fig.17).