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Advanced Materials

Job finished! But... What happened? We have made a good model, worked in the illumination setup... but there is anything sating this is a C.G. picture. Many times the problem is we want to see the first G.I render and we don't have care of our materials.

In this tutorial, we will create many basic materials very useful explaining step by step what to do. This materials are plastic, wood, chromed metal, glass, metallic paint, water and velvet.
We will use VRay, but this tutorial can be followed by another render engine users, as finalRender, Brazil or MentalRay.

To get advanced of this tutorial, we must know many concepts:

• Color: chromatic shade of an object. We can use a only color, or a bitmap.
• Specular highlights: bounce of the light come from a luminous emitter. The rougher (surface) the refracter (light over it). The most used are the Blinn (plastic, wood, almost every material), Anisotropic (CDs, or similar) and Multi-Layer (more attractive).
• Opacity: level of transparency of an object. It can be configured with a value (%) or with a bitmap.
• Reflexion: feature of many object to reflect the light. It can be set up with a percentage, and the glossiness.
• Refraction: feature of the transparent materials or translucent to change the trajectory of the photons which pass through it, distorting the image seen through them. The amount of variation of the trajectory is determined by the Index of Refraction (IOR).

Once explained this concepts, and before to start the "nice" part, we are going to see how to do a very useful effect which we will use in almost all the materials: the "Fresnel reflection".

The "Fresnel reflection" is a kind of bounce of the light which only works in the perpendicular parts of the objects (with the camera). Is the realest for plastics, glasses, porcelain, etc.

To do this effect is more or less easy:

1. Add to the "Reflection" a "Falloff" map.
   
    
   
    
2. Select as kind of "Falloff" the "Fresnel" one.
   
   
   
    
3. Do "clic" on the "NONE" button of white color, and add there "VRayMap". If we use another render engine we will use the respective raytrace map, or the "Raytrace" for the scanline render.
   
    
   
    
4. The "Fresnel" reflect is done. If we want to blur the reflect, we only need to turn the "Glossy" check box on, and try with differents values of the Glossiness.
   
   

Once seen this, we are prepared to begin with our materials.

• Matte plastic (Standard Material)

1.      Assign a color simple (Diffuse) or a picture (Bitmap). This will be the color of our object.

2.      Use a white specular color, with a low intensity (Specular Level = 20 - 30) and diffuse enough (Glossiness = 10 - 20).

3.      To improve the final look we can use a "Fresnel" reflect very blurred.




 

• Polish plastic (Standard Material)

1.      Assign a color simple (Diffuse) or a picture (Bitmap). This will be the color of our object, as in the matte plastic

2.      Use a white specular color, with a high intensity (Specular Level = 200 - 500) and very sharp (Glossiness = 85 - 95).

3.      Apply a clear "Fresnel" reflect.




 

• Wood (Standard Material)

1.      Use a picture (Bitmap) as the image of the wood we wanted, or the procedural material of the MAX called "Wood". Is adviced to use a bitmap because of the realism of this one (though if we get a good procedural we won't need to add a mapping to the wooden objects. In both cases, is used to be needed a desaturation (use as "Diffuse" a grey color (128,128,128) and change the percentage of the bitmap (or procedural) to 80 - 90%).

2.      Change the color of the specular to amber or similar, of low intensity (Specular Level = 20 - 30) and very  widespread (Glossiness = 10 - 20). It can be improved with a “Multi-Layer” specular, as in the example.

3.      We can simulate the bump copying the "Diffuse" map to the "Bump" box. The intensity will be changed depending on the contrast of the "Diffuse" map. Try different levels of bump until it works.

4.      If the wood is recent varnished, we will use a sharp "Fresnel" reflect with a 70 - 90% of intensity. If the wood is matte or if the object is old, we can use the "Glossiness" option in a "Fresnel" reflect with a  50 - 70 % of intensity.




 

• Chromed metal (Standard Material)

1.      To get a not too bright reflect, we must use a dark "Diffuse" color (dark grey or black).

2.      The specular will be white and very sharp (Glossiness = 85 - 95) and with a huge intensity (Specular Level = 200 - 500). It can be enhanced with the “Multi-Layer” specular, as it is in the example.

3.      Apply a common reflection (not “Fresnel”) set to 100%.

NOTE: the "quality" of the chromed depends COMPLETELY on the environment that surrounds the object. The richer environment (a finished 360º complete and full scene), the better result.




 

• Glass (VRayMtl Material)

We are going to create this material using the "VRayMat" of the VRay render engine. Doing that we will see the facility of using this new material.

1.      In the "Diffuse" color select a very dark color (better black), to avoid the bright reflecfts.

2.      Change the black color of the "Reflect" (no reflect) with white (maximun reflection). Activate the "Fresnel reflections"  (easier than standard way seen before).

3.      The refraction works exactly the same way of reflection. Change the black color (no refraction) with white (maximun refraction).

VERY IMPORTANT: to get a "real" glass, we must use the specific Index Of Refraction (IOR) of the glass (1,52 more os less). If we use another value the effect will be wrong.

Also, we can do variations of this glass as the following ones: 

• Tinted glass: the glass can be tinted with the color we want. We only need to do some test to get the exactly tint effect, due to the thickness of the object. To get this, change the white color of the “Fog color” with the desired and change the “Fog multiplier” until we get the wanted tint amount.
  
  
  
   
• Not flat glass: this is a very interesting glass, and can be used in screens, windows, etc. We only need to use a bump map. In this case, it's made with a noise map in the "Bump" button.
  
  
  
   
• Acid glass: it could be a variation of the last material, but with a very small size of noise. To do this we don't need a bump map, because the VRayMat has an option to get this effect. We only need to activate the “Glossiness” value from 1 (perfect glass with no distortions) to the value we want (0,8 is the value of the example). The smoothness of this effect depends on the “Subdivs” value: the higher the smoother (but it increase the render time).
  
  
  
  
  
   
• Metallic paint (Standard Material)

1.      In the “Diffuse” color button add a “Falloff” map (due to the effect of the real metallic paint) not a basic color. Once into the "Falloff" options, change the first color with the desired color of the object (blue, red...) and the second one with a very darker version of the first color, or even black.

2.      To enhance the specular shine use a “Multi-Layer” one (it is a mix of two specular shines). The first specular must be a white one, very intense (Specular Level = 300 - 500) and very sharp (Glossiness = 90 - 95). The second specular must be of the color of the object, but brighter, and diffuse enough (Glossiness = 15 - 30), and its intensity will be controlled by a “Celullar”, “Noise” or similar map, but always using a very small size. This way we can get the "grease" effect.

3.      Apply a “Fresnel” reflect (in the metallic paint case, we can use a 20% common reflect).




 

• Water

At the begining, we must think about wwhat kind of water we need, transparent water (if we are going to see what is under the sea), or opaque one (if we only want it refrecl). If we need transparent water we will use a "VRayMtl" material due to the possible problems with the shadows if we use a "Standard" one.

• Transparent water (VRayMtl Material)

1.      To avoid the bright "Fresnel" reflects we will use the black as the "Diffuse" color.

2.      Change the black of the "Reflect" box to white and check the “Fresnel reflection” on.

3.      Also, modify the black box of the "Refract" to white (total refraction). The Index Of Refraction (IOR) must be 1,33.

4.      We get the relief using a “Noise” map ("Regular" or "Fractal" as we want).

NOTE: is very important to activate the “Affect Shadows” checkbox of the “VRayMtl” material to process correctly the color.






(changing the size of the "Noise" map)
 

• Opaque water (Standard Material)

1.      The “Diffuse” color will be a lightly desaturated blue (relatively next to grey) and dark enough (the blue of the example is RGB: 28, 48, 58).

2.      A nice specular shine is made using the “Multi-Layer” one. The primary specular will be a white one, of a high intensity (Specular Level = 200 - 500) and very sharp (Glossiness = 85 – 95). The secondary specular will be light blue, with not too much intensity (Specular Level = 20 - 35) and very diffuse (Glossiness = 20 – 30).

3.      Use a “Fresnel” (remember the "Falloff" technic) reflect in the “Reflect” button.




 

VERY IMPORTANT: similar to the chromed effect, the water quality depends directly on the environment. If we can't get a nice reflect, we could use a bitmap to get a reflect different to the real one. You can get this with the "Reflection/refraction etc environment" - "Override MAX's" VRay's option in the render engine configuration window.
 

• Velvet (Standard Material)

1.      The key of this material is it's color, because the lack of specular shine, reflect or similar. The appropiate effect is produced by the “Falloff” material applied to the “Diffuse” button. The upper color of the "Falloff" material will be garnet (in this case), and the lower one pink (not pastel pink).

2.      Though the effect would be almost achieved, we could improve it adding a little "Noise" to the "Bump". It must be very little and fractal.

Selection of the original table of Jon Reynolds about Reflect and Refract values 

If you like this tutorial, please write a comment or a suggestion in the "Suggestions" section. Thanks