Hello Guys.
So this is my first Post on blenderartists.org (dont ask, why…) and i’m really curious, what you guys think.
By the way: this project is almost enirely made with blender. Only the blue lines behind and around the graffiti were made with black ink.
And just because it’s really ridiculus: Personal Records, i have broken with this image:
-most work time … about 50 hours i guess.
-most renderlayers (i used 6)
-most blenderlayers: there are objects in 10 diffrent layers
-most objects: 42!!! (Not each one is visible in the final render, i have to admit)
-longest object: 106 m
-most shaders: 30
-most render-time … somwhere between 6 and 10 h … i guess.
-most compositing nodes: about 92 (That’s totally nessesary.)
-most pixels: 4K-resolution! (but because of the crash below, my final file is “only” 3072 1728")
-most ridiculus crash: the compositor ran out of working storage. Fortunately, i saved the renderlayers just to be shure, so i didn’t had to render this again.
This looks really great! I am writing a book on Blender and was talking about how I have never seen car light streaks in 3D. Thanks for giving me an example. 
Great job!
Pretty cool.
My advice would be to add focus to either the light streaks or the graffiti. Right now they are both a bit dim and also similar in terms of how much space they take and their place in the frame.
The piece would overall be stronger if you let one or the other ‘steal the show’ more.
That’s actually true, and i did this on purpose. If either the graffiti or the car light were more in focus, the image wouldt suddently become unbalanced. The Car light is on the right and the graffiti on the left. And the car is attracting attention because of value and hue and the graffiti is atratcting attention, because it’s in focus and because it’s a font. When you lay over a golden ratio-texture you can se, that the right car light was even supposed to be a guiding line towards the graffiti … i know, it didn’t work, and i see your point, but i didn’t find a better solution. :-r
Sorry, if i destroyed your book (;D) But anyway: here’s the explanation, how i did it:
I used simpy a emitting volume combined with a gradeint and a noise texture. To get rid of fireflyes, i moved the volumes into diffrent renderlayers. There is a red car light in my main layer, only visible for glossy rays, a second car light in it’s own layer and a thord one in the rain-layer, wich is not visible for camera rays.
The inluence on fog and smoke is made in the compositor.
[To the moderator: i coudn’t edit my reply to shadowcamero, because it isn’t visible, jet. So if you couldt add the following to my reply, thad’d be great. Thanks!]
So you see: i had to do a lot of cheating to get a good result, wich might be a reason, why this effect isn’t seen very often blender.
By the way: currently, there is an audi-advertisment in german TV where a similar effect is sort of this red fluid of a HUGE thermometer. They combined a red smoke system, emitted from the autobody and the light streaks. But i couldn’t find it in the internet.