Blog archive


Ambient Occlusion

In computer graphics, ambient occlusion is a shading and rendering technique used to calculate how exposed each point in a scene is to ambient lighting. For example, the interior of a tube is typically more occluded (and hence darker) than the exposed outer surfaces, and the deeper you go inside the tube, the more occluded (and darker) the lighting becomes. Ambient occlusion can be seen as an accessibility value that is calculated for each surface point. In scenes with open sky this is done by estimating the amount of visible sky for each point, while in indoor environments only objects within a certain radius are taken into account and the walls are assumed to be the origin of the ambient light. The result is a diffuse, non-directional shading effect that casts no clear shadows but that darkens enclosed and sheltered areas and can affect the rendered image's overall tone. It is often used as a post-processing effect.


Ambient Occlusion image

source -

What is PBR (Physically Based Rendering)

What is PBR?

For complete guide on PBR visit Allegorithmic's  page.

Basically physically based rendering is a method of rendering and shading. This techique provides more realistic representation of how light interacts with model surface. 

PBR Workflows

There are 2 workflows that will produce the same material results.

  • Metallic/Roughness
  • Specular/Glossiness

Metallic workflow

Metallic workflow is made out of minimum 3 textures:

  • Base color (RGB) - engine will use it to interpret diffuse reflected color and also metal reflectance
  • Metallic - Grayscale - it tells the engine what parts of material are metallic(reflectice) and which are not. For instance white value is 100% metal, black 0% metal. Value between white and blue, for instance light grey will show transition between metal and non metal material, for instance a bit of dust.
  • Roughness - Grayscale - engine will use this to create either smooth surface(white) like glass or rough like concrete(grey-black). It can be use to create small details like scratches, fingerprints etc.