We used Autodesk vRed to make the car, and this image with its intricate raindrop meddling was a particular challenge
As always, the CGI process is grounded in observations of reality. Ivo spent time looking at how we perceive raindrops, and found that the ideal solution for light was the use of spheres, because the raindrops have natural sparkles – from light bulbs, windows and so on. Due to their hemisphere form as the drops hit a surface, the raindrops catch light very quickly from the surrounding world – at night those are the only sources of light.
A lot of light will reflect and refract in the water – and because the raindrops are so small, this is the only way to make them come alive.
To do this, we used high-resolution rain textures with displacement mapping. However, because we wanted to be flexible it was important to react fast on changes, so we used both triplanar and UV mapping.
Working with triplanar mapping gives us flexibility because we can change the form of the raindrops interactively without making any UVs, which is alway a time consuming process. As we have a lot of geometry (High Density Geometry) we can’t make UVs everywhere. A good example is the windshield – there I had to make UVs because we had windscreen wipers that have a specific movement. But for the rest of the car we used triplanar mapping for flexibility.
It was important to treat sections of the car individually, because some parts that are more “windy” then others, and the rain will “stretch” more on the surfaces that don’t receive so much wind while driving.
Also some elements are not as simple to add as you might imagine! We wanted moving, blurred windscreen wipers of course… but this took a lot of thought to get right. It took a lot of time painting where and how the raindrops are, depending on the motion of the windscreen wipers.
Here’s a little animation where you can see the borders of the wipers, and the render.
(animation to come)
The rendering took a lot of time as well – we used Full Global Illumination with a lot of samples…and of course only one sphere wasn’t enough, so we had to use two or three of them…however we are really pleased with the end result – the detailed work paid off beautifully.
Agency: Kemper Kommmunikation
Photographer: Erik Chmil
Creative Director: Nadine Kubis
Post-Artist: Thomas Fritz / Recom Stuttgart
CGI-Artist: Eugen Albrandt / Recom Stuttgart
CGI-Artist: Ivo Stanev / Recom Stuttgart