Epic Games shows off the new Unreal Engine 4 shading model and materials workflow.
Developers are increasingly gravitating toward physically-based shading for high-end film and game production because it allows them to more easily author beautiful, realistic materials that hold up under all sorts of lighting conditions. Unreal Engine 4’s new shading model and materials workflow offers a welcome reprieve from the tedious, expensive methods of the past.
Epic’s new materials pipeline helps artists leverage the power of physically-based shading in a visually friendly way. Materials are easier to implement than ever before, with support for numerous content creation methods that provide equally stunning results in-engine.
UE4 materials take advantage of node-based visual scripting, and the engine is designed so that desired changes can be propagated throughout the game world in real time. Whether a surface is constructed with one material or built via the layered method described below, materials in UE4 are kind to game performance, look fantastic, and give artists total control over aesthetics.
In the video above, the tricycle on the left contains eight individual material elements, with five unique materials placed within those slots. The one on the right utilizes material layers, which blends materials together to a single asset that can be applied, shared and reused as needed.
This evolution in materials is especially significant because layers can now be painted on at the pixel level, as opposed to the traditional method of applying changes to individual polygons. This can save loads of man hours, especially because UE4 assets can be edited, saved, and shared on the fly.
Since materials can now be mapped per-pixel, artists have the ability to change that mapping at runtime. Consider a tree in which one material defines bark and another defines char as the tree burns. An artist can change the mask at any time, and the char can simply appear where it's needed during gameplay.
The benefit to this approach is multifold. Since artists can abstract away individual types of materials, e.g., tree bark versus wood char, there is no need to overcomplicate a single material network by defining several different types within one material, which is what older methods require. This technique yields materials that are inherently simpler because they can be created faster and are easier to edit down the pipeline, if necessary.
In addition, the mask that defines each material layer’s placement can itself be modified and animated during gameplay. The potential applications that take advantage of this perk are limitless: Consider torn fabric exposing the skin beneath, or streams of black oil snaking across a character's flesh. Artists can even simulate character morphing by switching to a completely new type of material, such as shifting skin to steel or chrome – all changing at runtime, and all while maintaining fast and efficient editability for artists.