In this blog post, I'll detail the process of creating a versatile metal shader material in Blender Cycles, all achieved without the need for unwrapping the mesh's UV. This material is constructed using two distinct sets of node groups, specifically the edge wear nodes and the noise map mixed texture nodes, both contributing to its unique texture effects. The metal textures employed have been sourced from ambientCG, offering a range of colour variations for both the metal texture itself and the edge wear component, catering to diverse application scenarios.
My primary application of this material has been in rendering mechanical 3D models, allowing me to realistically depict industrial metal surfaces.
The heart of this material lies in its ingenious edge wear nodes group, inspired by the tutorial 'The RIGHT Way to do Edge Wear (in Cycles!)' by YouTuber Christopher Fraser. This effect is orchestrated through a combination of two bevel nodes, responsible for identifying the mesh's edge angles. Subsequently, a subtract node calculates the intersecting portions of the mesh's bevel. Enhancing this, a scratch black-and-white texture map is superimposed onto the bevel, imparting a dynamic quality to the edges. To ensure a non-repetitive appearance, a noise texture is integrated to serve as an alpha mask for the scratch texture map. This novel node group captivates me, as it generates bevels and scratches in response to mesh edits, a technique I hadn't previously explored within Blender. Comparatively, while I've been delving into Substance Painter lately, I find similarities to its smart materials, which leverage various masks based on factors like mesh face sharpness or ambient occlusion. However, unlike Substance Painter, the shader I've developed in Blender doesn't necessitate UV unwrapping, enabling instant visibility of changes made to the mesh.
The second focal point, the noise map mixer nodes group, involves the amalgamation of two sets of texture maps—diffuse, metalness, normal, and roughness—with the nuanced influence of a noise texture map. This approach yields satisfying outcomes for most small-to-medium-scaled meshes. Nonetheless, on larger-scaled meshes, some texture repetitiveness becomes noticeable, albeit mitigated by the presence of the noise texture map.
For integration into game engines such as Unity or Unreal Engine, a pragmatic solution is the use of smart UV unwrapping to generate a UV map, followed by leveraging the Blender plugin "SimpleBake" to facilitate texture baking. While the results are impressive in 4K/8K maps, they may not replicate the crispness of the original Blender Cycles material.
Material Result Showcase