“Next Gen car – part 4 ” by Valentin Nadolu
This is how the mesh looks with normal vertex based shading.
This is how the mesh looks with normal maps applied in High Quality Rendering.
2. The Ambient Occlusion Map:
This is a bit easier to explain: basically, the ambient occlusion (AO) map contains the amount of „visibility” stored for each pixel. The more occluded that point is in 3d space in relation to its surroundings, the darker the pixel will be on the AO texture. I will not go into detail about how this is calculated, I will stick to showing how it is generated and used. Because occlusion is influenced by all the objects in the scene, this map does not require the low and high-res models to be separated to minimize the number of intersections.Texture generation is similar in steps to the generation of normal maps. The next image presents some of the settings used. One thing to mention is that for the AO baking, the „Max Search Depth” setting is ignored. This is replaced by „Occlusion Max Distance”, which usually require a value larger than 50 to give proper results.The value for „Occlusion rays” is directly proportional to the quality of the final texture and the rendering time. For a test render, a value of 16 will be enough, but to obtain a smooth texture, I use a much higher value, usually a power of 2 (64, 128). Be careful, high values in this field will cause the rendering time to increase dramatically!The resulting image is a grayscale that can be put on top of the painted color texture using Multiply. This will add depth to the diffuse texture, making it look more realistic.
Usually ambient occlusion maps take more time to bake than normal maps, so some patience is required. Do a lot of test renders with low “Occlusion Rays” values to make sure all the details show up on the map before doing a full resolution render that can even take more than half an hour to complete.Now that these textures have been baked, you are ready to move on to the next and final chapter of this tutorial, texturing.
(c) Valentin Nadolu , www.amc.ro
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