Without a clear understanding of the functioning of the main material VRay - VRayMtl - it is not possible to use this visualizer qualitatively. This article is intended for all those who want to use the VRay and 3ds Max visualizer more professionally. The explanatory part (about the main parameters of VRayMtl) of the article is based on examples, which will contribute to a more complete understanding of the subject.
Parameter "Roughness" (roughness of the surface of the material).
This example demonstrates the effect of the “Roughness” parameter. Notice that the more important the roughness is, the more the material becomes “flat” and “dusty”.
Parameter roughness
The color of the “Reflection” parameter.
This example shows how the color of the “Reflection” parameter affects the overall reflectivity of the material. Also, the reflection color works as a filter for diffuse color (the stronger the reflection, the less diffuse color affects the material).
The parameter “Reflection glossiness” (reflection glossiness).
Here, as you can see, is presented how Reflection glossiness and Highlight glossiness affect the VRay material, that is, they create glare and blur reflection.
The parameter "Energy preservation" (the mode of conservation of the material diffuse reflection of light).
This example shows how Energy preservation controls the diffuse color darkening mode through reflection.
Option "Fresnel"
Here you can see the effect of turning on the “Fresnel” option. Notice how the value of IOR (index of refraction, index of refraction) changes the reflection force of the VRay material. In this example, the reflection color is set to completely white (255, 255, 255).
The parameter "Anisotropy" (anisotropy).
This example shows the use of the “Anisotropy” parameter. Notice how the value of the parameter affects the stretching of the reflection horizontally or vertically.
The parameter "Anisotropy rotation" (angle of anisotropic reflection).
The “Anisotropy rotation” parameter is shown here, which adjusts the reflection anisotropy angle of the VRay material. For all images in this example, the Anisotropy parameter is set to 0.8.
The color of the “Refraction” parameter.
In this example, you will see how the material for the glass is created using the color of the “Refraction” parameter. For example, the material was used with a gray diffuse color, white for Reflection and the “Fresnel” option enabled.
The parameter "Refraction glossiness" (blur refraction).
This example is somewhat similar to the Reflection example because the low value of the “Refraction” parameter increases the blurriness.
refractions, making it look like frozen glass.
Parameter "Refraction IOR".
This example demonstrates the effect of using the “Refraction IOR” parameter. Notice how the light rays bend when passing through a material with a value greater or less than 1.0. If the refractive index is 1.0, you will get a completely transparent material (that is, like air). I note that if you want to make an object transparent, it is better to use a transparency map (slot “Opacity”) than refraction, because the first one is calculated much faster in VRay.
The parameters "Refraction depth" and "Reflection depth" (the maximum number of possible refractions and reflections).
Here is the parameter "Refraction depth", which controls the quality of refraction (in quantitative terms). You can see that with a low value of the parameter, we get an extremely unrealistic result. You should also pay attention to how Reflection depth affects areas with internal reflections (quantitative influence is similar to Refraction depth).
The “Exit color” parameter for Refraction.
This parameter is most suitable for realistic images that contain VRay materials with a large value of the “Refraction depth” parameter. See how the red areas get smaller as the “Reflection depth” and “Refraction depth” parameters increase.
The parameter "Fog color" (the color of the turbidity of the material).
This parameter controls the color of turbidity to refract the material. Notice that the thicker areas of the object become darker, because the “Fog color” parameter also performs the function of light absorption.
Parameter “Fog multiplier” (turbidity multiplier).
This example shows the effect of the “Fog multiplier” parameter. Small values reduce the absorption of light, and large values increase it.
Option "Fog System Units Scaling".
As you can see in this example, the option “Fog System Units Scaling” (this option appeared in VRay material recently) activates the determination of the real size of the objects being refracted, so light absorption occurs in physically correct conditions. At the teapot in the scene, the radius is four meters. With the “Fog System ...” option disabled, we can see through the kettle. But if you turn on the “Fog System ...” option, then VRay will take into account the actual size of the teapot during the image rendering, which means that more realistic light absorption will be calculated.
Dispersion option
This example shows the possibility of including dispersion in VRayMtl, as well as different values for the “Abbe” parameter. This is also a new option for VRay (it is available in VRayMtl since VRay version 2.0).
BDRF (determines the model of the reflection of light from the material).
Here you can see all the BDRF models available for the VRay visualizer. Pay special attention to the formation of glare produced by different models of BDRF.
Option "Soften".
This option helps to smooth the transition between dark areas of the material and reflections of the reflections.
