To add an opacity mask in Substance Painter, a crucial first step is to select a shader that supports transparency or alpha information. Without the correct shader applied to your material or mesh, Substance Painter cannot render or display opacity effects, regardless of any masking you perform on layers.
Substance Painter offers various shaders, and those that handle transparency are necessary for opacity mapping. As demonstrated in the provided reference, examples of such shaders include:
- Metal Roughness with Alpha blending
- Cutout Alpha (Alpha cutout or Alpha Test)
Choosing between 'Alpha blending' and 'Alpha cutout/Test' depends on the desired visual effect.
Steps to Enable Opacity Masking
- Open Substance Painter and load your project.
- Navigate to the Shader settings. This is typically found in the Texture Set Settings window under the 'Shader' dropdown.
- Select a shader that supports transparency.
- The reference highlights the use of a "cutout Alpha cutout or Alpha Test" shader as a common way to show how opacity works. This shader type typically results in sharp, binary transparency (pixels are either fully opaque or fully transparent).
- Alternatively, selecting "Metal Roughness with Alpha blending" allows for semi-transparency, where pixels can have varying levels of opacity.
- Once the appropriate shader is selected, Substance Painter is configured to interpret alpha information.
Applying the Opacity Effect
After setting up the shader, you can then add opacity information to your material. This is typically done by:
- Adding a fill layer or paint layer.
- Ensuring the layer has the Opacity channel enabled (check the channel list for the layer).
- Adding a black mask to the layer.
- Painting with white on the black mask (or using generators/procedurals) to reveal the layer's effect where you want opacity to occur.
- The color or value within the Opacity channel of the layer itself determines the level of transparency in the masked areas (black for fully transparent, white for fully opaque, and shades of gray for semi-transparency when using an Alpha Blending shader).
Summary of Key Shader Types for Opacity:
| Shader Type | Transparency Type | Common Use Cases |
|---|---|---|
| Metal Roughness with Alpha blending | Semi-transparent | Glass, fabric, particles, effects with fading |
| Cutout Alpha (Alpha cutout or Test) | Binary (fully opaque/transparent) | Foliage, fences, decals with sharp edges, hair |
By selecting a shader like the "cutout Alpha cutout or Alpha. Test" or "Metal Roughness with Alpha blending," you enable Substance Painter to process alpha information, allowing you to effectively add and control opacity masks using standard masking techniques on your layers.
