Rules for Physically Based Rendering
Physically Based Rendering (PBR) are a set of rules to achieve a believable look. These images follow PBR rules in a more ore less strict manner.
- Do not violate energies conserving laws. An object can not emit more energy, in this case light, than it receives.
- Make a distinction between metallic and dielectric materials. They reflect in a very different manner.
- How reflections can be seen on a surface depends on the viewers position relative to the object. On gracing angels we have reflection, but not at facing angels. This is called the Fresnel effect.
- Diffuse looking materials reflect the environment, but more blurry compared to metals.
- In the real world every surface has roughness, even a mirror.
- There are no sharp edges in real world objects.
Real world photos used
Most of these images are based on two photos.
- For the environmental light HDRI images from www.hdriheaven.com are used. They serve as a light source and can be seen in reflections.
- To texture the object a second photo is needed. This is the source of the albedo color.
- And this photo will be used for mesh displacement.