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Developers from Airship Images talked about the technique, that helped them to model impressive realistic hair for characters in The Division. Great insight into a complex topic.
One of the areas we specialise in here at Airship is the creation of real-time hair. Over the last 5 years we’ve contributed to numerous titles with real-time hair, consistently pushing the bar in terms of quality and efficiency. We have developed our own internal tools to make hair creation a more artistic process.
Perhaps surprisingly, one of the tools that plays a huge part in the process is ZBrush. It’s such a versatile application that it finds it’s way into so many areas of our process, no matter what we are working on.
There are many ways to approach building real-time hair. They vary in terms of tri count budget, style and engine. The budget for the Division’s hairstyles was slightly above the average but still fairly low because of it’s MMO nature. This meant that the typical workflow of placing individual hair cards to ensure entire scalp coverage wouldn’t be suitable.
We begin by creating a low poly hair “cap” that will be used as the final low poly and also a base to paint on. The cap itself has a wide coverage and captures all the transitionary detail on the front, back and sides.
Wrapping the cap to the head allows us to use the hairstyle on multiple characters. The cap also allows to us achieve certain depth effects when viewed from various angles in engine.
The cap is then divided up to allow for the best possible resolution. We then paint onto the divided cap to create a realistic base. The layers are built up using ZBrush’s layer system, which allows us to control a bottom, middle, top and strand layer separately.
The brush system in ZBrush is so versatile that we can accurately modify our brushes and build a painting style consistent with realistic human hair. Using a variety of custom made brushes we paint the haircap using reference images of the intended style. ZBrush makes this a breeze, being one of the only 3D painting programs out there without substantial brush lag when using custom brushes.
The top layer is for splays, this is where a lot of realism can be brought in with small split ends and strands that wisp away.
When each layer has been finalised, we extract each layer separately and bring them into Photoshop.
The layers are arranged and colour corrected depending on the end result. In the Division, each hairstyle needed to be tintable so the end result was a desaturated shade of blonde, this allowed tinting of every colour needed.
The next step is important and usually out of our hands – the engine has to be compatible with flow maps and anisotropic shading. We worked with Ubisoft Massive on The Division to ensure our workflow was implemented correctly into their engine and the results turned out fantastic. We paint the flow map inside Photoshop using the cone method.
Then comes the planes. We have developed extensive hair tools in house which run in Autodesk Maya. The tools let us place planes down in a more artistic way, giving us the freedom to concentrate on the style, coverage and look in engine.We place all our hair planes down differently depending on which engine it is going into, as all engines have their strong and weak points. This greatly affects the way the styles need to be built.
We place all our hair planes down differently depending on which engine it is going into, as all engines have their strong and weak points. This greatly affects the way the styles need to be built.
We hope you’ve enjoyed this insight into the methods we use to create high-quality hair and hopefully you’ve learned something new!