What is PBR?
Physically Based Rendering, or PBR, is a method for simulating how light interacts with surfaces in a way that closely matches real-world physics. It’s become a foundational part of modern 3D graphics, especially in industries like gaming, visual effects and product visualization, which are increasingly using photogrammetry and 3D scanning to optimize their workflows. PBR ensures your materials behave realistically under different lighting conditions, no matter what you scan.
The Basics of PBR
PBR is not a single technology or tool, but rather a principle and a workflow. The aim is to have the same material look correct and realistic in any lighting environment, whether in an outdoor scene or a dimly lit interior. This is achieved by using standardized texture maps that define how light should interact with a specific surface.
One of the biggest advantages of using PBR in 3D scanning is the reduced workload for 3D artists and designers. Instead of manually painting or tweaking material properties for hours, artists can start with scan data that already includes accurate normal, roughness, and albedo (base color) maps. For product designers, game developers and digital artists, this means faster iterations, more realism and ultimately, higher-quality results.
PBR Workflows
There are two different workflows used in PBR: Metalness/Roughness and Specular/Glossiness. The names come from the specific texture maps used to communicate surface information, which is explored more in the next section. Both workflows aim to simulate realistic materials by controlling how light interacts with a surface, just done in slightly different ways.
Metalness/Roughness is now considered the more standardized approach to PBR, mainly used in game engines like Unity and Unreal Engine and preferred for its simplicity. On the other hand, Specular/Glossiness is used in older rendering engines, especially in VFX and CAD pipelines, and allows for more nuanced control of lighting and reflective properties.
Both workflows describe the same surface properties, but from slightly different angles. They are mutually exclusive, meaning you either use one or the other, not both.
Understanding PBR Texture Maps
PBR relies on several texture maps to describe different physical properties of a material. Here are the most important ones:
Albedo (Base Color) Map
Used in both workflows, this map contains the base color of the surface, with no shading, lighting, or reflections. It’s essentially what the object looks like in perfect, diffuse lighting.
Roughness Map
The roughness map determines how smooth or rough a surface is. A low roughness value results in sharp, mirror-like reflections, while high roughness leads to soft, diffuse ones. It’s the key to making something look more polished or more matte.
Metalness Map
This binary map tells the renderer which parts of the surface are metal and which are not. White (1) means metal, black (0) means non-metal.
Glossiness Map
Essentially the inverse of the roughness map, communicating the same concept: how shiny the surface is. A highly glossy surface has concentrated reflections, while a matte surface scatters light more broadly.
Specular Map
The specular map defines the intensity and color of specular reflections. Instead of a binary map indicating if the surface is metal or not, this map communicates a scale indicating the base specular reflectance value of different parts of the object. The specular workflow allows for more control over non-metallic materials that still exhibit colored or varying reflective properties.
Normal Map
A normal map adds fine detail to a surface without changing its geometry. It stores the orientation of surface normals in RGB values, which the renderer uses to simulate bumps, wrinkles, and grooves under lighting. These are typically captured via photogrammetry or generated from high-resolution geometry. To understand more about how normal maps work, they were explored in more detail in our previous article here.
How PBR Maps Are Created
Photogrammetry plays a central role in the creation of PBR maps by capturing both high-resolution geometry and texture data from real-world objects. With the right lighting setup and camera angles, it’s possible to generate not just the base color (albedo) and 3D shape, but also additional maps like normal, roughness and even specular or metalness.
Outside of photogrammetry, PBR maps are typically created through a combination of manual and procedural methods. Artists may use physically based materials from libraries or generate maps using software like Substance Painter, which simulates wear, texture and light response based on custom brushes and masks. High-poly 3D models can be sculpted and then baked down to generate normal and curvature maps, while roughness and specular maps are often derived from grayscale height or reflection references. This workflow, although more controlled, can be time-consuming and may lack the physical grounding that photogrammetry provides.
Conclusion
By understanding and properly using maps like normal, roughness, specular, and albedo, creators can produce models that not only look good in one scene but remain believable in any environment. As the field evolves, we’re likely to see PBR become even more essential in both traditional 3D pipelines and emerging areas like real-time simulation and mixed reality.
