reflactions & refractions

8/10/2019 Reflactions & Refractions

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Metallic Materials

To create a metallic material, we need to add a reflection layer. Then we have to increase the reflectionamount using the reflection IOR value. The reflection IOR value is located in the Fresnel effect inside thereflection layer mapping.

How to created a metallic material?

Basic Chrome material:- Add a reflection layer

- click on the M near the Reflectioncolor. You will see the fresnel effectenable by default.

- Increase the IOR value 20.

Notes:We considerate metallic reflection anIOR value between 6 to 26.

IOR value between 1 to 5 are mostlyplastic reflection.

Filter

By default the color of the reflection is white, But you can tint the reflection using the reflection Filter.This option allows you to change the color of the reflection producing different metals color.


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Glossiness

In the reflection layer you will find two glossiness option. The Hilight glossiness and the reflectionglossiness. The Hilight is create by reflecting a very bright light source in the material. The HilightGlossiness control the shape of the Hilight. The Hilight value has to be the same of the ReflectionGlossiness in order to be physically correct. Some types of material do not reflect the light clearly duethey have uneven surfaces. In that case we use the Reflection Glossiness to control the sharpness of thereflection. You could find this effect in some matte finish metal, wood, plastics, etc.

Note:All of these materials were rendered with the same Hilight and Reflection glossiness (0.8). Notice that thereflection is not 100% sharp. With the glossiness we can add some blurriness to the materials and in thisway we could make anodize metals and blurry metal. The same option should be use to make blurryplastics and some wood materials.

Tip:You can increase the glossiness subdivision to improve the quality of the glossiness and remove thenoise. This option will increase the rendering time on this material. A good value for the subdivision couldbe something between 22 - 40. We usually recommend 32 for the subdivision.

Refraction Layer (Glass Materials)

Refraction is the phenomenon of light going under the surface of an object and the ray get bended insideproducing, in this case, the glass material.

In V-Ray for Sketchup we can create a glass material by adding a refraction layer. Usually the refractionlayer is bellow the Diffuse layer and the diffuse layer block the effect of the Refraction layer. In order to beable to see the refraction effect, we have to use transparency in the diffuse layer.


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How to create a Glass material?Basic Glass material:- Add a reflection layer- Add a refraction layer- Change the diffuse layer transparencycolor to 100% white

To add a Refraction layer:- Right click over the material name- Select create Layer- Select Refraction layer

Note:If you use a gray-scale color in the diffuse

transparency slot, you will make thediffuse layer semi-transparency.Therefore, you will be able to see thediffuse color at some grade.Tips:If you remove the refraction layer to aglass material, you can create fake

Architectural glass with only Reflectionlayer. Due the material doesnt have therefraction layer the calculation for thismaterial is faster. You can use thismaterial in a simple plane to simulateglass windows

Real Glass Material Fake Architectual Glass


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Tinted Glass Materials

There are two basic way to t int a glass material using V-Ray. The first one is using the refraction color. Asyou remember in the reflection layer we use the filter to tint the reflection, in the refraction layer we coulduse the refraction color to tint the refraction. This option will tint the reflection even around the geometry.This is not the physically correct way for most of the glass material, but it is very useful to create Plexiglasand transparent plastics.

The second method to tint the reflection layer is using the Fog Color. This is the physically correct effect,because the coloration of the refraction depend on the thickness of the object. Thicker part of the objectwill appears darker while thinner parts will appear lighter

Using the Refraction color

How to tint the reflection using theRefraction color?We need to have a basic glass material:- Click on the refraction color- Select the desire color for the glass.

Here we have some examples of tinted glass using the refraction color. Notice how the color is eventhough the whole model. The first picture is just to show you how the material looks without color.


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Using the Refraction color

How to tint the reflection using the Fogcolor?We need to have a basic glass material:- Click on the Fog color- Select the desire color for the glass- Adjust the Fog color multiplier to 0.1 (justfor this example, this value could bedifferent, depending on the desired colortone)

Here we have some examples of tinted glass using the Fog color. Notice how the color is change

depending on the thickness of the model. The thinner areas appear lighter, while the thicker areas appeardarker. This is the physically correct effect of the tinted materials.

The fog color depends of three aspect, the size of the object, the fog color and the color multiplier. Forexample if you increase the color multiplier the thicker part will appear darker and vice-verse.

Glossiness

As in the reflection layer, we also have a glossiness option in the refraction layer to add blurriness into theglass material. The glossiness option is very useful to create materials as frosted glass or acid glass.


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Glossiness= 1.0 Glossiness= 0.8 Glossiness= 0.4

IOR Value

As in the reflection layer, we also have a glossiness option in the refraction layer to add blurriness into theglass material. The glossiness option is very useful to create materials as frosted glass or acid glass.

IOR value= 1.0 IOR value= 1.55 IOR value= 2.417 IOR value= 4.0

All the renders above were rendered using different IOR value. Notice how the effect is stronger if weincrease the IOR value.

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