Creating complex and visually stunning shaders in Unity often requires access to multiple UV sets. This tutorial will guide you through the process of exposing and utilizing additional UV sets within Shader Graph, empowering you to unlock advanced texturing techniques.
Understanding UV Sets
Before diving into the implementation, let's briefly understand what UV sets are. UV coordinates, essentially, map a 2D texture onto a 3D model's surface. A single UV set provides one such mapping. Multiple UV sets allow you to apply different textures to the same model simultaneously, opening possibilities for detail maps, normal maps, and more.
Exposing UV Sets in Shader Graph
Unity's Shader Graph doesn't directly expose additional UV sets by default. We need to manually add the necessary nodes to access them. Here's a step-by-step guide:
Step 1: Create a New Shader Graph
Start by creating a new Shader Graph asset in your Unity project.
Step 2: Accessing the Additional UV Set
- Add a Property Node: Add a new Property node to your graph.
- Set the Property Type: Change the property type to
Vector2. - Name the Property: Give it a descriptive name, for example,
_UV2. This name will be crucial later when assigning the UV set in your material. - Set the default value (optional): You can optionally provide a default value.
Step 3: Connecting the UV Node
- Add a UV Node: Add a UV node to your graph. By default, this node provides access to the primary UV set (
UV0). - Add a Vector 2 Node (optional): Optionally, add a Vector 2 node to adjust the UV values before applying them. This is useful for offsetting or scaling.
- Connect to your Custom Property Node: Connect the output of the UV node to the input of your newly created
_UV2property node. This step is crucial.
Step 4: Using the UV Set
Now you can use the _UV2 property node as you would any other input for your texture sampling nodes. Connect it to your Texture Sample node's UV input. This will sample the texture using your secondary UV set.
Step 5: Assign in Your Material
- Create a Material: Create a new material and assign your newly created Shader Graph asset.
- Access the UV Channel: Within the material's inspector, you'll find your
_UV2property. This is where you will select the desired UV channel from your model's mesh. This step is vital; selecting the correct channel is critical for proper rendering. Ensure your model is correctly setup with multiple UV sets in your modelling software.
Advanced Techniques and Troubleshooting
- More than two UV sets: You can repeat this process to expose as many UV sets as your model requires. Simply create additional Property nodes and connect them to corresponding UV channels.
- Channel names: Remember to use consistent and meaningful names for your properties to avoid confusion.
- Mesh UV mapping: Make sure your 3D model is correctly exported with the appropriate UV sets in your 3D modelling software (Blender, Maya, 3ds Max, etc.). Incorrectly mapped UVs will result in distorted textures.
- Shader compilation errors: If you encounter shader compilation errors, double-check your connections and property types within the Shader Graph.
By following these steps, you'll effectively expose and utilize multiple UV sets in your Unity Shader Graph projects, unlocking a world of advanced texturing possibilities. Remember to always test and iterate to achieve your desired visual results.
