In this tutorial you’ll learn how to create an albedo map from a photographic texture using ShaderMap. Albedo maps are commonly used in Physically-Based Rendering and serves as the color input also know as the diffuse map.
“An albedo map defines the color of diffused light. One of the biggest differences between an albedo map in a PBR system and a traditional diffuse map is the lack of directional light or ambient occlusion. Directional light will look incorrect in certain lighting conditions…” – marmoset.co
Follow these steps to generate an albedo map:
Step 1: Load a Photographic Texture
From the Start Screen load the texture you want to convert to albedo as a Color Texture. Allow the default maps to be setup. In this example I will be using a Rock texture which can be downloaded at the bottom of this tutorial.
Step 2: Add an Albedo Map to the Project
Move your mouse over an empty cell in the Project Grid. Click the plus (+) button to bring up the “Add Node to Project” dialog. Scroll down and find “Map: Albedo [Diff]”. Double-click the map to add it to the project.
Step 3: Adjust Shadow and Highlight
Select the Albedo map in the Project Grid. Use the “Shadow” and “Highlight” sliders to decrease the amount of shadows and highlights in the image. On the rock texture I use the following settings:
- Shadow – 70
- Highlight – 85
Step 4: Set the Luminance of the Image
An important part of PBR albedo maps is that they have the correct luminance value for the material. In this example I am working with a rock texture, I know that Rock generally has a linear luminance of 0.33 and an sRGB luminance of 0.6. Using the “Level” control I can adjust luminance of the image which is displayed in the properties “Linear” and “sRGB”.
For the rock example I increased the Luminance as follows:
- Level – 19
Below you can see two displacement materials applied to the ShaderMap dynamic plane geometry. The first uses the original texture is the diffuse channel and the second material uses the albedo as the diffuse. Notice that the albedo map allows for variance in the scene lighting as the shadows and highlights are not baked into the texture. Using the correct luminance creates a more realistic simulation of rock. The same lighting and material settings (except for diffuse map) are used on both renders.
Download the project and source texture below. Keep in mind that the albedo map plugin can create colored artifacts on textures of low quality such as compressed images.
The SM3 Project File can be downloaded here: Albedo ShaderMap Project
It should be used with the source image located here: http://www.mb3d.co.uk/…Rock_Moss_UV_CM_1.jpg
Find more great free and seamless textures at: http://www.mb3d.co.uk/