For a better understanding of the differences between Metallic and Specular workflows, we will modify the Albedo and Specular/Smoothness maps that are used on a Specular setup material, in order to adapt them to the Metallic workflow. The material to be generated will feature both metallic and non-metallic parts, with various smoothness levels.
For this recipe, we have prepared a Unity package containing a battery model and its original material (made with Standard Shader—Specular setup). The package includes two image files for the original Albedo and Specular/Smoothness maps which, throughout the recipe, should be adapted for use with the Metallic setup. The package is available in the 1362_04_02 folder.
To create a basic material, follow these steps:
- Import the
battery_prefabUnity package into a new project. - From the Project view, select the battery_prefab element. Then, from Inspector, access its material (named Battery_MAT) and change its Shader to Standard (as opposed to its current shader—Standard (Specular setup).
- From the Project view, find the
Battery_specularmap and rename itBattery_metallic. Open it in your image editor (we'll use Adobe Photoshop to illustrate the following steps). - Find the layer group named Specular and rename it Metallic. Then, fill the light gray layer (named Layer 2, in the Metallic group) with white (R: 255, G: 255, B: 255), and the dark gray layer (named Layer 1, in the Metallic group) with black (R: 0, G: 0, B: 0). Save the file:
- Go back to Unity. From the Inspector view, set the modified Battery_metallic map as the Metallic map of the Battery_MAT material. Also, set None as the Albedo map for that material. This will give you an idea of how the material is coming along:
- Now, let's adjust the Albedo texture map. From the Project view, locate the
Battery_albedomap and open it in your image editor. Then, use the Paint Bucket tool to fill the black area of Layer 2, in the Albedo group, with light gray (R:196, G:199, B:199). Save the file:
- Go back to Unity. From the Inspector view, set the modified Battery_albedo map as the Albedo map of the Battery_MAT material.
Your material is ready, combining visual properties based on the different maps that you have edited and assigned.
The visual aspect of the battery is a combination of three properties of its material: Metallic, Smoothness, and Albedo.
To compose the dark red part of the plastic body, for instance, we have mixed the following:
- The Metallic map (RGB): Black (for a non-metallic appearance)
- The Smoothness (the Alpha Channel of a Metallic map): Light gray (for a glossy appearance)
- The Albedo map: Dark red (for a dark red color)
The light red portion, on the other hand, combines the following:
- The Metallic map (RGB): Black
- The Smoothness (the Alpha Channel of the Metallic map): dark gray (for a matte appearance)
- Albedo map: red (for a red color)
Finally, the brushed metal used for the top and bottom covers combines the following:
- The Metallic map (RGB): white (for a metallic aspect)
- The Smoothness (the Alpha Channel of the Metallic map): blurred grey noise pattern (for a brushed appearance);
- Albedo map: light grey (for an iron-like appearance)
Remember to organize your layers in to groups named after the property that they are related to.