Ambient Occlusion Lighting is a lighting technique which makes it possible to increase in a very appreciable manner the realism of a 3D scene. It can be considered as a lower cost solution to imitate the total illumination techniques that are usually used in ray tracing softwares.
To arouse your interest, here is an example of a 3d real time rendering result that exploits the Ambient Occlusion, resulting from the Static Ambient Occlusion Lighting Demo (called thereafter Static AO demo):
Fig.1 - Ambient Occlusion rendering.
The AO technique (AO for Ambient Occlusion) is mainly focused on the ambient term of the lighting equation used in real time calculations. Here is the equation:
where If is the intensity of the pixel final color, Ia the intensity of the ambient color, Id the intensity of the diffuse color and Is that of the specular color. For more details regarding the calculation of the Id and Is terms, please refer to the Bump Mapping . tutorial.
In this equation, the Ia term is constant for a given 3d object. That means that if the lighting equation is reduced to If = Ia, the 3d object will be colored in a uniform color and we won't be able to distinguish its 3d morphology. Figure 2 shows the scene of the Static AO demonstration illuminated by a constant ambient intensity:
Fig.2 - Constant ambient intensity rendering.
We can't see a thing. By correctly modulating this ambient intensity (with the occlusion factor which we will explain further) we obtain the result of figure 3:
Fig.3 - Modulated ambient intensity rendering.
And now the 3d objects of the scene appear very clearly. Therefore, an illustrated explanation of the AO would say that it consists in applying a variable modulation factor to the ambient intensity factor of the scene. That can be summarized by the following equation:
where Ia is the final ambient intensity, IA the constant ambient intensity and occ() a function that depends on the vertex which gives the modulation factor.
Let us now start giving a soul to the occ() function.
To arouse your interest, here is an example of a 3d real time rendering result that exploits the Ambient Occlusion, resulting from the Static Ambient Occlusion Lighting Demo (called thereafter Static AO demo):
Fig.1 - Ambient Occlusion rendering.
The AO technique (AO for Ambient Occlusion) is mainly focused on the ambient term of the lighting equation used in real time calculations. Here is the equation:
where If is the intensity of the pixel final color, Ia the intensity of the ambient color, Id the intensity of the diffuse color and Is that of the specular color. For more details regarding the calculation of the Id and Is terms, please refer to the Bump Mapping . tutorial.
In this equation, the Ia term is constant for a given 3d object. That means that if the lighting equation is reduced to If = Ia, the 3d object will be colored in a uniform color and we won't be able to distinguish its 3d morphology. Figure 2 shows the scene of the Static AO demonstration illuminated by a constant ambient intensity:
Fig.2 - Constant ambient intensity rendering.
We can't see a thing. By correctly modulating this ambient intensity (with the occlusion factor which we will explain further) we obtain the result of figure 3:
Fig.3 - Modulated ambient intensity rendering.
And now the 3d objects of the scene appear very clearly. Therefore, an illustrated explanation of the AO would say that it consists in applying a variable modulation factor to the ambient intensity factor of the scene. That can be summarized by the following equation:
where Ia is the final ambient intensity, IA the constant ambient intensity and occ() a function that depends on the vertex which gives the modulation factor.
Let us now start giving a soul to the occ() function.
Occlusion Shader Unity Patch
Ambient Occlusion Unity
Ambient Occlusion is a post-processing effect that approximates crevice shadows in real time, darkening creases, holes, intersections, and surfaces that are close to each other. This gives a more realistic appearance to parts of objects where ambient light is blocked out or occluded. In this tutorial you'll learn how to add Ambient Occlusion to your Post Processing Stack and configure it for.
Occlusion Shader Unity Definition
- Unity - Ambient Occlusion artefacts. Ask Question Asked 4 years, 1 month ago. Active 4 years, 1 month ago. Viewed 1k times 0 $begingroup$ When I create two cubes from Unity Component menu. Browse other questions tagged unity shaders global-illumination ambient-occlusion.
- The good news is, Unity comes with a pretty high-end PVS system built right in. It’s based on a third-party tool called Umbra, which by all accounts is a state-of-the-art PVS system (actually, it’s a collection of PVS systems for different use cases). If you need occlusion culling in your game, this is where you should start.