Physically-Based Rendering (PBR) textures allow you to represent realistic shading and lighting by using multiple types of texture images, or maps, on a single object. Combining multiple texture maps can more accurately simulate color, roughness, and reflectivity in any lighting environment and can enhance the visual elements of your assets and environment.
You can use a variety of applications and workflows to create PBR textures during the modeling and texturing process of a custom 3D object as long as Roblox Studio supports the texture maps.
This guide provides instructions on setting up your mesh objects to use PBR textures maps and describes common use-cases and best practices for Roblox's supported PBR texture maps. When creating your own surfaces, see Material References for common material values and image comparisons as well as clothing examples.
Enabling Surface Appearance
You can add PBR textures to any MeshPart by adding a SurfaceAppearance object which overwrites the original assigned texture. In general, you can't modify SurfaceAppearance properties by scripts during an experience because the engine requires some pre-processing to display these graphics. Similar to adding a basic texture, each texture image map must point to the appropriate uploaded image asset ID.
To enable surface appearance for a MeshPart:
Insert a SurfaceAppearance from the contextual menu.
When you are ready to add texture maps to your SurfaceAppearance object, you can click each map property to browse and set the appropriate asset ID for each image:
Studio currently supports 4 types of PBR texture maps: Color, Normal, Metalness, Roughness. Each of these maps correspond to an important aspect of the object's surface appearance. Texture maps only change visual appearance and don't affect the geometry of the MeshPart object.
See the following examples for an overview of Roblox's supported texture maps and additional resources:
The ColorMap property sets the color data of the surface, including any transparency present in the map. See Color (Albedo) for additional information.
The color, or albedo, map determines the color of your texture and consists of mostly color information with little to no lighting or textural information. For additional customization, you can also add transparency in your albedo texture by adding opacity to your image map.
For objects that require partial or complete sections of transparency, such as grass, leaves, lace, or decals like dirt or grunge, you can use various alpha modes to apply transparency to your color map. If your color map image format supports alpha channels, you can apply a grayscale alpha map where 0.0 is opaque and 1.0 is transparent. Similarly, when using an image format such as a .png, any opacity on the color map applies as transparency on the asset.
You can apply transparency in two different behaviors by setting the following AlphaMode values:
- Overlay — Overlays the ColorMap over the underlying mesh's MeshPart.Color. Color maps using Overlay reveal the base color of the mesh anywhere transparency is present. This is the default setting.
- Transparency — Removes the visible mesh based on transparency in the ColorMap. This renders the mesh see-through and does not reveal the original mesh color whenever transparency is present.
You can use Overlay to reveal sections of the mesh's original color. Since the transparent areas of the color map expose the underlying color, you can design an unique texture map that partially or fully reveals the mesh's Color property for custom skin tones or other situations with unique colors.
The following example demonstrates how the Overlay mode works using a white sphere reference:
The following example uses the Overlay mode for custom characters, revealing the character's original skin-tone:
See Custom Skin Tone for additional details on optimizing an overlay for skin and similar applications.
You can use the Transparency mode to create complex or extremely fine objects, such as lace or netting, by removing visible parts of the mesh as an alternative to sculpting the mesh geometry. Since this does not affect the geometry of the mesh object, this can allow you to create detailed objects without the performance impact of an intricate mesh model.
The following example demonstrates how a partial and full transparency in this mode visually removes sections of the mesh:
The normal, or surface, map adds texture depth to your surface and behaves similarly to a height map. As a result, the effect may fade or intensify depending on the viewing angle and lighting environment. When a normal map is not present, the value is set to 0.0.
In the following figure, you can switch between the mesh reference and the map reference for comparisons of normal map values:
The R, G, and B channels of the image correspond respectively to the X, Y, and Z components of the local surface vector. A uniform image of color [127, 127, 255] translates to a completely flat normal map. Roblox only supports OpenGL format - Tangent Space normal maps.
Normal maps prominently affect the visual surface of a mesh and can accentuate awkward seams in your texture. Whenever possible, keep your texture seams hidden to avoid visual issues with your mesh.
Roughness, or microsurface, maps determine how light is spread across your model’s surface. When roughness is at 0.0, the surface doesn't scatter light at all resulting in a much sharper and brighter reflections and glossiness on your material. At 1.0, light and reflections evenly scatter over the model resulting in a less reflective matte-like surface.
Roughness may impact how reflective an object is at different angles, referred to as the Fresnel effect. See Fresnel for more details and best-practices to maintain consistent reflective behavior.
See the following figure for comparisons of various roughness map values:
Fresnel refers to the amount of reflection of a surface in reference to the current viewing angle. Studio's Fresnel processing aims for physical real-world accuracy, although you may get unexpected specular contribution at certain angles even with rough surfaces. In some cases, you can compensate by making your roughness map around 0.1 more rough to achieve a consistent lighting response with your materials.
Even though Roblox renders this lighting effect accurately, the brightness and reflectivity of a surface may not respond consistently between your texture content creating software, such as Substance Painter, and Studio. See Clothing Examples for differences in rendering between applications.
Metalness determines the reflectivity of a surface. Metalness values range between 0.0 and 1.0. Roblox sets the default value to 0.0 if a metalness map is not present.
See the following figure for comparisons of various metalness map values:
Different PBR renderers use various types of workflows for processing reflectiveness. Studio only uses the metalness workflow which determines whether a material is a nonmetal or a metal, sometimes referred to as an insulator or conductor.
In most cases, you should set this value as either at 0.0 (non-metal) or at 1.0 (metal). You can use partial metalness values when creating more uncommon surfaces with moderate reflective properties, like satin or silk. This practice can subtly fake the reflections in the material to highlight the color from the color/albedo map over colors reflected in the environment.