We relished the challenge of creating this CGI Porsche Panamera in the rain for a campaign from Kemper Kommmunikation with photographer Erik Chmil.
Here’s a look into how we made it. There’s a selection of 100% crops to zoom in on the details, and a video where you can feast your eyes on the perfectly rendered raindrops on the CGI Porsche.
We used Autodesk VRED to make the car. This execution, with its intricate raindrops, was particularly interesting. The finished image (above) is packed with finely observed details.
As always, the CGI process is grounded in observations of reality. CGI artist Ivo Stanev spent time studying the interaction between the raindrops and the surface of the car. The water acts like hundreds of tiny lenses and we found the best way to light them was to use high resolution HDRI spheres.
Due to their hemisphere shape, formed as the round drops hit a flat surface, the raindrops catch light from the many sources in a night scene like this- street lamps, headlights, windows and so on. This is what makes them sparkle.
To do this, we used high-resolution rain textures with displacement mapping. However, because we wanted to be flexible it was important to react quickly to changes, so we used both triplanar and UV mapping (the process of projecting a 2D image to a 3D model’s surface for texture mapping )
Working with triplanar mapping gives us flexibility because we can easily change the form of the raindrops, especially as the CGI modelled Porsche has High Density Geometry. A good example is the windshield, where UV mapping allowed is to model windscreen wipers with a specific movement. For the rest of the car we used triplanar mapping for flexibility.
It was important for us to show the effect of the wind, changing the shape of the raindrops as they move along the surface of the car’s body.
Also some elements are not as simple to add as you might imagine! We wanted moving, blurred windscreen wipers of course…so we carefully painted where and how the raindrops moved, depending on the motion of the windscreen wipers.
The rendering took a lot of time as well – we used full Global Illumination with a lot of samples…and of course only one HDRI sphere wasn’t enough, so we had to use two or three of them.
We are really pleased with the end result – the painstaking work paid off beautifully.
Fly though the details in our video here…