The baking of an ambient occlusion
by Enrico Valenza, Pierre-Armand Nicq, Romain Caudron
Blender 3D: Designing Objects
- Blender 3D: Designing Objects
- Table of Contents
- Blender 3D: Designing Objects
- Blender 3D: Designing Objects
- Credits
- Preface
- 1. Module 1
- 1. Straight into Blender!
- 2. Robot Toy – Modeling of an Object
- Let's start the modeling of our robot toy
- Using the basic modeling tools
- Modeling the head
- Modeling the antenna
- An introduction to the Subdivision Surface modifier
- Modeling the thunderbolts
- Modeling the eyes
- Modeling the chest
- Modeling the neck
- Modeling the torso
- Modeling the buttons
- Modeling the fork
- Modeling the main wheel
- Modeling the arm
- Using Blender Internal to render our Robot Toy
- Summary
- 3. Alien Character – Base Mesh Creation and Sculpting
- 4. Alien Character – Creating a Proper Topology and Transferring the Sculpt Details
- 5. Haunted House – Modeling of the Scene
- 6. Haunted House – Putting Colors on It
- 7. Haunted House – Adding Materials and Lights in Cycles
- 8. Rat Cowboy – Learning To Rig a Character for Animation
- 9. Rat Cowboy – Animate a Full Sequence
- 10. Rat Cowboy – Rendering, Compositing, and Editing
- 2. Module 2
- 1. Modeling the Character's Base Mesh
- 2. Sculpting the Character's Base Mesh
- 3. Polygonal Modeling of the Character's Accessories
- 4. Re-topology of the High Resolution Sculpted Character's Mesh
- 5. Unwrapping the Low Resolution Mesh
- 6. Rigging the Low Resolution Mesh
- Introduction
- Building the character's Armature from scratch
- Perfecting the Armature to also function as a rig for the Armor
- Building the character's Armature through the Human Meta-Rig
- Building the animation controls and the Inverse Kinematic
- Generating the character's Armature by using the Rigify add-on
- 7. Skinning the Low Resolution Mesh
- 8. Finalizing the Model
- 9. Animating the Character
- 10. Creating the Textures
- Introduction
- Making a tileable scales image in Blender Internal
- Preparing the model to use the UDIM UV tiles
- Baking the tileable scales texture into the UV tiles
- Painting to fix the seams and to modify the baked scales image maps
- Painting the color maps in Blender Internal
- Painting the color maps in Cycles
- 11. Refining the Textures
- 12. Creating the Materials in Cycles
- 13. Creating the Materials in Blender Internal
- 14. Lighting, Rendering, and a Little Bit of Compositing
- 3. Module 3
- 1. Overview of Materials in Cycles
- 2. Managing Cycles Materials
- 3. Creating Natural Materials in Cycles
- Introduction
- Creating a rock material using image maps
- Creating a rock material using procedural textures
- Creating a sand material using procedural textures
- Creating a simple ground material using procedural textures
- Creating a snow material using procedural textures
- Creating an ice material using procedural textures
- 4. Creating Man-made Materials in Cycles
- Introduction
- Creating a generic plastic material
- Creating a Bakelite material
- Creating an expanded polystyrene material
- Creating a clear (glassy) polystyrene material
- Creating a rubber material
- Creating an antique bronze material with procedurals
- Creating a multipurpose metal node group
- Creating a rusty metal material with procedurals
- Creating a wood material with procedurals
- 5. Creating Complex Natural Materials in Cycles
- 6. Creating More Complex Man-made Materials
- 7. Subsurface Scattering in Cycles
- Introduction
- Using the Subsurface Scattering shader node
- Simulating Subsurface Scattering in Cycles using the Translucent shader
- Simulating Subsurface Scattering in Cycles using the Vertex Color tool
- Simulating Subsurface Scattering in Cycles using the Ray Length output in the Light Path node
- Creating a fake Subsurface Scattering node group
- 8. Creating Organic Materials
- Introduction
- Creating an organic-looking shader with procedurals
- Creating a wasp-like chitin material with procedural textures
- Creating a beetle-like chitin material with procedural textures
- Creating tree shaders – the bark
- Creating tree shaders – the leaves
- Creating a layered human skin material in Cycles
- Creating fur and hair
- Creating a gray alien skin material with procedurals
- 9. Special Materials
- Bibliography
- Index
Now that we have the normal map set, we will improve our alien with another map called an ambient occlusion.
An ambient occlusion is a black and white texture that represents the contact shadows of a mesh. The contact shadows are the shadows produced by the small proximity of objects. In order to have a nice ambient occlusion, we need to increase a sampling parameter that corresponds to the "noisiness" of the shadows. The more samples you have, the smoother the shadows will be. This map will then be multiplied on top of our diffuse material color.
Note
Multiplying colors
In computer graphics, black is represented by a value of 0 and white by a value of 1. So, when we multiply a color with black, its result is 0, and when we multiply a color with white, its result is the color. For instance, we will take two colors, J and K, a pure blue that is represented by R(J): 0, G(J): 0, and B(J):1 (RGB means Red Green Blue), and white, R(K): 1, G(K):1, and B(K):1. When we multiply both, we will have R(J)*R(K) = 0 * 1 = 0, G(J)*G(K) = 0 * 1 = 0, and B(J)*B(K) = 1 * 1 = 1, so the resultant color is R:0, G: 0, and B:1. It is the original blue.
We will now follow the same principle as the normal map, but we will change the sampling value:
- The sampling slider is situated under the world tab of the Properties editor in the Gather subpanel. Even if it's grayed out, it will work for the bake. We will set it to 10 in our case. Don't go too high with this as it will increase your baking time.
- Now, refer to the normal map baking process, but instead of choosing a normal map in step 5, choose an ambient occlusion. Again, don't forget to add the blank texture in Edit Mode, and save it after the bake. You can also name your textures in the UV/Image Editor in the header with the corresponding text field.
The baked ambient occlusion map of our alien
In order to see the ambient occlusion applied to our mesh, we will have to add a new texture to our material. This is done as follows:
- First, we will select our alien, and then we will select the material that has the normal map on it in the Material tab of the Properties editor.
- We will, then, go to the Texture tab of the Properties editor and add a new texture below the normal map. In order to do this, we select the second slot and click on the big New button.
- We can now choose our ambient occlusion under the Image subpanel.
- Under the Influence subpanel, we turn the color slider on but we change the Blend Mode from mix to multiply, as we had previously explained. As you can see, this perfectly works in the viewport when the Texture shading mode is turned on. We can clearly see the contact shadows of our mesh around his eyes, for instance.
The alien with a proper topology (shown on the left-hand side) and with its normal map and ambient occlusion (on the right-hand side)
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