The fourth chapter mainly introduces the characteristics and details of some common materials in the real world, the author reminds us that we should always pay attention to the characteristics of nature's material in the real world, and strengthen our own thinking and keen observation and perception to realize the rendering is very helpful.
The author mainly analyses the following materials:
Plastic
Wood: Trees, wood, painted wood
Leaves and plants
Metal
Concrete and Stone: concrete, masonry, stone of nature
Skin
Hair and hair
Atmosphere
Translucent material: glass, water
Paint
The old worn-out material
Plastic
Plastic has many color shapes and even a different paint, but its material composition is consistent.
Most plastics consist of white or translucent substrates filled with stained particles like this
When light shines on a plastic object, some light is reflected on the surface of the edge, and at some special angles we see the color of the light (the highlight point) and the part becomes white (the color of the plastic matrix). Some light penetrates the material and is reflected from the dyed particles, which will absorb some of the wavelength of light, and reflect, and absorb the color of the light we cannot see, and we see that the color of the plastic is all the light reflected by the dyed particles. This effect is evident on smooth plastic.
On the rough plastic surface of the penetration and reflection is not uniform, at this time the high-gloss (specular reflection) range is very large and light, this is caused by two reasons:
1. The rough plane reflection direction is not the same, just by the glasses absorption of reflected light a lot less
2. Because the plane is rough, so there is a small bump, there will be a bump on the surface of the shadow, these surface bumps produced by small shadows blocking the incident light
The high-gloss color of the plastic comes from the color of the substrate, so basically the color of the Light & Matrix (white/translucent)
WoodThere are many forms of wood, trees in the forest, the floor of the house and so on.
Tree
The most important thing in the rendering tree is the rendering of bark and exposed wood, in nature the bark becomes rough because of the growth of the tree. All the details of the bark are derived from its geometry, as the bark is cracked and tilted to produce a dark and light relationship, and the upturned bark creates shadows and creates darkness, and the cracked bark inside does not receive the rays and becomes dark. If the bark is mapped from a real tree at this point, remember to dispose of the shadows and highlights, otherwise the game will result in incorrect results.
There may be lichen moss, etc. that make the roughness different.
Bark color is also not uniform, such as birch, such as a tree bark color inconsistencies, roughness is not the same, plus an additional gloss map can solve the problem
In addition, it is very simple to simulate the fracture of the tree and the warping of the geometry, that is, the surface subdivision plus displacement texture
Wood
The most notable thing in the wood rendering is the texture of the wood, which can be easily achieved by changing the color, such as a map, but the texture contains many features, and there are more bumps and wrinkles in the texture. Other places have different glossiness and roughness (perhaps due to uneven distribution of sap and tree oil concentrations).
Wood is a certain degree of anisotropy, the direction of the grain affects the way light reflects.
The wood that has been painted
General furniture and flooring are painted wood, the material retains the original color of the wood, but has a smooth surface can reflect a lot of light, the light paint reflected more than wood. Different gloss paints have different reflection colors and effects.
Gloss can reflect a material of the new and old, the use of the degree and quality, you can use a variable to adjust the reflection of the light paint and the proportion of the log to reflect the new and old paint wood level. However, if the wood is very old at this time, pay attention to the wood color map to do very old.
leaves and plants
Like bark, rendering plants is more than just a color map. They have veins and folds, and most of the leaves are smooth, rough, rough, and even small hairs that interact with each other. Calculation of illumination
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Most of the leaves and plants are translucent, and light rays penetrate the interior of plants and leaves, causing the plants and leaves to reflect, refract and absorb rays, creating an interesting phenomenon called subsurface scattering, so that the light is on the back of the blade, and we can see the internal structure of the blades from the front.
Unity3d Shader subsurface scattering (subsurface scattering)
Originally in the leafy rainforest, a large number of leaves blocked a lot of light, the interior dim, at this time to see the light to the leaves are bright green, indicating that there will be some light through the blade irradiation down, at this time the light carries the color of the leaves, so the lighting atmosphere is green.
Unity3d Real Plant rendering
Metal
Non-embroidered metal and plastic very much like, their surface is very smooth, so the high-gloss is very strong. But they are different, the metal is dielectric material, plastic is non-dielectric material, the reflective metal is more of its own color, and plastic high light is more of the color of light. For example, look at the reflection of the face of the floor, gold reflection is gold, black plastic reflection or the white color of the floor.
One important difference between the two is that the metal does not have a plastic-like substrate unless it is painted on a metal surface.
In addition, different metals reflect light differently because they have different molecular structures, so they differ in their microscopic levels of reflection. This structure can cause the reflective color of the metal to vary. The surface treatment of the same material is different from the reflective way, such as smooth steel and polished steel, such as.
Concrete and StoneConcrete
Concrete is composed of a variety of minerals and stone, is a composite material, so they have different roughness and surface structure, and there are a lot of bumps, produce a lot of small shadows, the light source position changes, the shadow will change, which also pay attention to the problem of mapping, remember to take the map in the real world to remove the highlights, shadows, And then light color, restore the most genuine material.
Bricks
The more common is the red masonry, the surface is still uneven, and each brick color is not the same.
Stone of Nature
The natural stone contains the above mentioned characteristics, different stones can give the player a feeling in the real environment.
Some games have a low number of polygons for stone, which is wrong, because the details of real stones exist both in geometry and coloring.
Skin
Skin rendering in the game to give people the most realistic effect, so that the player feels like in the real human interaction, the color of the human skin is basically consistent, some places will be because of the distribution of grease and wrinkles, pores and other surface structure of the different, and the same as the leaf surface scattering phenomenon.
Unity3d screen space human skin perception rendering & subsurface scattering
Atmospheric Effectsbloggers feel that this should not be put in the material to speak ...
Atmospheric effect is closely related to the atmosphere of the game, we can communicate the state and atmosphere of the game by controlling the atmosphere color, hue and concentration.
Unity3d Shader Real-time outdoor light scattering (atmospheric scattering) rendering
Translucent Material
Translucent material has reflections, refraction and chromatic aberration.
Unity3d BTDF Real-time refraction simulates a translucent object with roughness
Chromatic aberration: the refractive index of optical glass varies with the wavelength of the passing light wave, and its refractive index of the long wavelength is greater than that of long wavelengths, and we can observe the rainbow spectrum when white lights pass through the trigonous boundary. The rainbow spectrum caused by the refractive index of wavelengths is called dispersion phenomenon (dispersion).
The effect is this:
GlassReflection, refraction, and the effect of thickness on refraction
Smooth glass reflects the surrounding environment, the amount of light reflected in the angle of the eye direction, for curved glass, such as a goblet, away from the eyes of the sides (on the left) than the side of the eye (front) more reflective degree
The surface roughness of frosted glass is different from that of smooth glasses, and the reflection effect is different.
Water
In addition to the treatment of fluid fluctuations, water and syrup are different. Also pay attention to the water will produce caustics phenomenon. Clear water, turbid water, floating on the surface of oil and other turbid things.
For Rivers, to deal with the distance between eyes and water, close to the color change, crystal clear, far away can only see color.
Unity3d PBR Seawater Rendering
Unity3d to make his own water water effect (ii)
Unity3d make his own water water effect (i.)
the old materialIt is summarized as follows: wear, scratches, color changes, rust stains, character changes
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----by wolf96 http://blog.csdn.net/wolf96
Objects and materials for advanced lighting and materials
