- Is Ambient Occlusion Still Relevant?
- The Difference Between AO and Cavity Maps
- Final Thoughts
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Is Ambient Occlusion Still Relevant?
On this website, one of my very first tutorials was about setting up PBR textures in Blender and explaining the purpose of each texture. In that post, I described the role of AO maps as:
Description: AO textures are used to reflect fake shadows across the surface our mesh. It’s usage is not suggested within Blender’s Cycles engine since it is capable of tracing and calculating realistic shadows.
When we compare the technology available today with that of the early 2000s and now, the difference is enormous. We no longer need to compromise on many aspects to achieve a visually pleasing result. This idea prompts a question: If we can effortlessly calculate shadows in real-time, do we still require AO maps? After all, all ambient occlusion maps do is reflect ‘fake shadows’ across the mesh. The straightforward answer is yes, we still need AO maps, and they remain relevant. A more detailed explanation follows.
Then why do we still need ambient occlusion textures?
With Ambient Occlusion Map
No Ambient Occlusion Map
In modern texturing workflows, the AO map is often utilized more akin to a ‘cavity map,’ enhancing shader detail rather than capturing the most realistic representation of the mesh when light traces hit it. This adjustment aims to make the appearance more pleasing to the eye.
You might then wonder, what sets AO and cavity maps apart?
The Difference Between AO and Cavity Maps
An ambient occlusion (AO) map and a cavity map serve similar purposes in texturing, but they capture different aspects of the surface of a 3D model.
- Ambient Occlusion: Creates the illusion of simulated soft shadows by darkening areas where light has difficulty reaching. AO maps concern shading and lighting. We can think of AO maps as slides with a bunch of numbers on them, which describe to the render engine how much of the ambient environment lighting can reach the mesh’s surface point. In other terms, AO maps provide shadow information to the render engine and say ‘This is where the shadows should appear on this mesh.’ Darker areas in this texture type represent regions where light is occluded or blocked, while lighter areas indicate areas that receive more ambient light.
- Cavity Map: Cavity maps care about highlights such as cracks, crevices, and might also show where shadows and dirt might accumulate. They highlight the recessed areas such as hollows, cavities, or indentations. In this texture type, darker areas represent crevices or recessed areas where light is blocked or occluded. Lighter areas represent raised or protruding surfaces that catch more light. Some real-life examples of this would be human skulls (eye sockets, nasal cavity, and mouth are all recessed areas on a skull), brick walls (mortar lines between bricks), car tires (tread patterns between the raised sections), and computer keyboards (the depressions between keys and around the edges of the keys). So cavity maps are used to bring the details of the object one step forward while AO maps are used to improve shader’s overall appearance.
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Final Thoughts
If you’d like to learn how to create your own AO maps in Photoshop, I also have a tutorial for it here. If there is any confusing part in this post, feel free to contact me, and I’ll do my best to answer your question.
Note: If you are tired of watching video tutorials and would like to see more text-based tutorials like this one from me, you can support me on Patreon so I can dedicate more time to creating them.