When rendering and botany collide

The Concord grape is Welch’s greatest brand asset, and they needed to protect its integrity at all costs. So when Genuine pitched a whimsical campaign of social videos with anthropomorphized grapes as characters, we knew we had our work cut out for us. While our grapes would move whimsically, accompanied by lighthearted copy and upbeat music, visually they had to carry the iconic look of real Concord grapes in as photorealistic a treatment as possible.

I knew that rigging and animating grapes—little more than slightly oblong spheres—wouldn’t be the biggest lift for this campaign. Instead, of the eighty hours invested in the first deliverable, almost forty were spent on materials and look development.

Research

What gives Concord grapes their iconic purple color? If I was going to build a physically accurate material for our hero grape, I had to become a mini-expert in botany. Grapes of all varieties get their color and finish from three parts of their anatomy: the flesh, the skin, and the “bloom,” a waxy coating that grapes secrete in order to protect themselves from bacteria and harsh weather. The flesh of a Concord grape, believe it or not, is bright green (with the occasional reddish individual). Its skin, by contrast, is a dark purple, similar to a cranberry in certain kinds of light, and sometimes leaning cooler, toward blueberry, in other circumstances. Finally, the bloom looks whitish with just a hint of lavender, and its waxy texture significantly diffuses the underlying colors and reflectance. Nailing the material meant striking the right balance between the different properties of those three blended layers, and rendering the results under the right kind of light.

Working in Cinema 4D’s Physical renderer, my approach was to build up these different layers just as they’d appear in nature. Due to Physical’s speed limitations, I had to forego proper subsurface scattering in favor of layered red and blue noise to approximate the interplay between the flesh and skin, but otherwise I did my best to build up reflectance, diffusion, and bump in a 1:1 relationship with the grape’s anatomy. Keeping the bloom separated from the rest of the material also made iterating the treatment across multiple grapes a little less of a headache.

Challenges

The biggest hurdle in The Mighty Concord’s look development was the Physical renderer. While beautiful, consistent results were absolutely gettable, those results came at a significant cost in render time. Because of this, small tweaks were tough to test interactively, which in one case led to unexpected texture sliding issues later on in the campaign’s lifecycle. In addition, Physical’s lack of a node-based material editor (R20 can’t come soon enough!) and the finickiness of the Set Driver/Set Driven method of quick Xpresso rigging made iterating the materials for multiple grapes a lame manual job. If we’d kicked off this campaign with the tools we’ll have in 2019 instead of in 2016 (not to mention the power of a nice third-party GPU renderer), that forty hours’ worth of look dev might have been ten or twelve.

Technical challenges aside, we also ran into issues of context. This entire campaign was working toward a deep respect for the client’s product, so they were understandably particular about where the overall color of the material netted out. However, up until that point, Welch’s usually showcased their grapes in context: in bunches, on vines, or bountifully piled in baskets. When shown in isolation, without a reference for scale, and especially on a novel color like the pale purple field we’d developed to brand the campaign, we ran into significant issues getting the iconic purple color dialed in just right. The simultaneous contrast we’d created between the grape and its environment actually shifted how the color we were building was perceived, with the grape appearing too much like a cranberry in one draft and too much like a blueberry in the next. When I sampled colors from my renders and compared them to photo references, we could tell the renders were right on the money, but the grape just didn’t look right in context. It was a tough balancing act that ultimately required us to introduce an “incorrect” amount of blue in the color grading phase to sell the grape as purple on that particular background. This solution was so delicate that if the light purple background was turned off, the whole effect would fail. Color’s a tough challenge any day of the week, and material work for food, in particular, introduces layers of complexity and unique challenges. I can only imagine what it’s like to be a food photographer!

All 3D execution, compositing, and sound design by Jared Flynn.
Agency: Genuine
Client: Welch’s