Infinite Diversity of the Materials

Creating the material is almost half of the Octane. This topic is perhaps the most serious and must be studied continuously. The times you used to create material by imaginary settings are over. It's time to stand on the ground of the real world and look carefully at your surroundings. Because if you want to create a good material, you have to know and understand the interaction between the material and the light in real world. How are the materials in reality? By the simplest definition, light photons hit the surface and act according to the properties of that surface. What affects the appearance of a surface is the structural and optical behavior of it. This behavior determines the way of interaction with the surface and the ray. When light hits a surface, three types of interaction occur:

1- Can be Absorption by the surface.

2- Can be Transmission to the other side of the surface.

3- Can be Reflected from the surface.

材质的无限多样性

创建材质几乎是Octane的一半。 这个话题也许是最严肃的，必须不断研究。 通过虚构设置创建材质的时间已经结束。 是时候站在现实世界的基础上，仔细看一下周围的环境了。 因为如果您想创建一种好的材质，则必须了解并理解现实世界中材质与灯光之间的相互作用。 现实中的材质如何？ 按照最简单的定义，光子撞击表面并根据该表面的性质起作用。 影响表面外观的是表面的结构和光学行为。 此行为决定了与曲面和射线交互的方式。 当光线撞击表面时，会发生三种类型的交互作用：

1-可以被表面吸收。

2-可以传输到表面的另一侧。

3-可以从表面反射。

The combination of these three interactions usually occur. In reality none of these features are 100%. Because the Law of Energy Conservation always works. According to this law, you can not find the material that reflects or absorbs 100% in nature.

Some materials absorb certain wavelengths of light. They also reflect some of them. This effect is called fluorescence effect. Interaction of the radiance energy to the surface follows the Law of Energy Conservation. Accordingly, the sum of the energies absorbed, transmitted and reflected by a surface equals the sum of the energies coming to the surface. This rule applies separately for each wavelength. So, There is no need to measure of these three energy interactions separately. These quantities are determined in ratio to the incoming energy (ie, relative). These ratios are different for each material and surface geometry. However, these ratios seem to be more related to matter structure. Accordingly, for a material surface, these ratios are called absorbance, transmittance, and reflectance, respectively.

Now that we are traveling infinite variety of real materials, we need to know and understand the tools underneath. Octane was already good at creating the materials, but now it's getting closer to the reality thanks to the new BRDF models. In the upcoming chapters, we will examine Octane's classic materials and new BRDF models in detail.

Remember, all the materials in the real world, no matter how simple they seem to us, actually offers a magnificent world which we want to disappear, discover and enjoy. If you're ready now, let's dive into the depths of this world.

这三种相互作用通常会结合在一起。实际上，这些功能都不是100％。因为《节约能源法》始终有效。根据该法则，您无法找到自然反射或吸收100％的物质。

一些材质吸收某些波长的光。它们也反映了其中一些。该效应称为荧光效应。辐射能与地面的相互作用遵循能量守恒定律。因此，被表面吸收，透射和反射的能量之和等于到达该表面的能量之和。该规则分别适用于每个波长。因此，无需分别测量这三种能量相互作用。确定这些数量与输入能量（即相对能量）的比率。对于每种材质和表面几何形状，这些比率是不同的。但是，这些比率似乎与物质结构更相关。因此，对于材质表面，这些比率分别称为吸收率，透射率和反射率。

现在，我们正在旅行的材质种类繁多，我们需要了解和理解下面的工具。 Octane已经很擅长于创建材质，但是现在有了新的BRDF模型，它已经越来越接近现实。在接下来的章节中，我们将详细研究Octane的经典材质和新的BRDF模型。

请记住，现实世界中的所有材质，不管它们在我们看来多么简单，实际上都提供了一个我们想要消失，发现和享受的宏伟世界。如果您现在已经准备好，让我们深入了解这个世界。