1. MATERIALS Chakrit Watcharopas Reference:
The Essential Blender: The Official Guide to 3D Creation with the Blender Open Source Suite  
Author Roland Hess Publisher No Starch Press Publication Date 

2. Managing Materials
Materials are created and linked to objects in the Links and Pipeline tab of the Material Buttons (F5)
The Material buttons will display the material for the active object in the 3D view
Once a material is linked to an object, it is quite simple to change or remove that link
Changing material is just a matter of choosing a different material from the drop down menu

3. Components of a Material
Blender materials each have four main components:
base color
shaders
reflection and transparency
textures (will be mentioned in the next class)

4. Base Color Under Material buttons, "Col" sets the overall color
"Spe" sets the base colors for Specular
"Mir" sets the base colors for Reflections

5. Shaders
Diffuse shading explains the way that renderer calculates the general shading of the object
Lambert: Blender's default shading option
Lambert is a good shading model for plastics and other glossy, fairly smooth substances

6. Shaders (2)
Minnaert shader can affect the way that light plays on the portions of your geometry that face the camera directly, as well as the portions that are perpendicular to it
Minnaert is useful for cloths, e.g., velvet, and can also be used for giving backlight effect

7. Shaders (3) Oren-Nayer is a shading for matte surfaces
Try using Oren-Nayer, unless you are working with cloth, plastic, etc
Although Oren-Nayer doesn't generate any texturing based on the "Roughness" value, it simulates the more diffuse scattering
As such, Oren-Nayer works well as a basis for human skin materials

8. Shaders (4)
Toon shading breaks the shading into three flat regions - shadow, mid-tone and highlight
Toon allows you to control the sharpness of boundaries between them
Using correctly in combination with Toon specular shader and edge rendering option, can produce an effect much like the standard three-part shading of hand- drawn animation

9. Shaders (5)
Although Diffuse has slightly different controls, it also has a Ref (Reflectance) value
Ref represents amount of light that reflects from the surface and reaches the camera
A Ref value of 0.8 means that 80% of the light that reaches the surface from lamps is used for shading purposes
For most cases, Ref with 0.8 is a good starting point

10. Shaders (6)
The lower set of controls is for materials that have Specular highlights
Specular highlighting is a way of faking the reflectance of light on a surface
Many times real world materials will appear more believable if Spec value is 0 or near it

11. Shaders (7) Spec value indicates intensity of the highlight
Metallic objects should have highlight colors (Spe color from the Material tab) near to their base color
Hard value controls the size of the highlight
"Harder" substances like glass or diamond exhibit tiny, tight highlights, while softer substances (like cloth) have a larger highlight

12. Shaders (8)
Blinn specular shader pairs well with Oren-Nayer diffuse shader for most matte and naturally occurring surfaces
Phong works well for glossy plastics
Phong and CookTorr can produce good results for shiny metallics

13. Reflection and Transparency
Reflectance in Shaders tab is different from Reflectance in Mirror Transp tab
Reflectance in Mirror Transp tab refers to actual visible reflections, ones seen on a mirror

14. Reflection and Transparency (2)
We can simply create reflective surfaces in Blender by enabling "Ray Mirror" option in the Mirror Transp tab
Adjust RayMir between 0 (no reflection) and 1 (full reflection)
Above method uses Blender's Raytracer
Raytracer follows light rays from the camera back to their source
It creates great effects, but can be costly in terms of render time

15. Reflection and Transparency (3)
In order for "Ray Mirror" to work, make sure that the "Ray" option is turned on in the Scene buttons (F10)
If you want your reflective objects to have an overall color cast (like the tinted reflection in red and green Christmas balls), you will need to set the "Mir" (Mirror) color in the Material tab

16. Reflection and Transparency (4)
Alpha in CG terms tells how much light passes through a surface
Alpha scale runs from 0 (fully transparent) to 1 (completely opaque)

17. Reflection and Transparency (5)
Changes to the Alpha slider, labeled "A", will be reflected immediately in Material preview
To visualize Alpha effect in the 3D view, select the object, switch to the Object buttons (F7) and enable the "Transp" button on the Draw tab

18. Reflection and Transparency (6)
There are two ways for Blender to render Alpha
If you don't need to simulate refraction, the best way to do is to use zTransparency
If you need refractive realism, you will need to use raytraced transparency

19. Reflection and Transparency (7)
To use zTransparency, enable the "ZTransp" button on the Links and Pipeline tab of the Material Buttons
To use raytraced transparency, make sure that zTransp is disabled in the Material tab, then enable "RayTransp" in the MirrorTransp tab
IOR slider just below the RayTransp button controls the Index of Refraction
Find the value of Indices of Refraction for glass, water, sapphire and diamond

20. Reflection and Transparency (8)
Two objects rendered with Ztransp (left) and with Ray Transp (right)