The Random Flow add-on in Blender having these starter preset materials will allow you to quickly test out the look of your model in render. These shader group nodes are designed to let you easily create grunge, dirt, edge wear and rust shader effects to your model without the hassle of using any textures, which lets face it are hard to come by without making your own. They are also very versatile and can be layered on top of each other especially the quick dirt group node - by connecting two of