Structuring Materials ( tutorial 2 )


Creating materials can be as simple as painting them on or as complex as layering element used in the material channels, or even creating specific texture maps in image editing programs, for color, bump, reflection, transparency or any material channel.

Assigning Material Channels

When creating materials the first thing is to decide what the material will be, then applying the properties of that material using the correct material channels. This is a rather simple but very important process to create a realistic looking material. For instance a piece of old wood has a grainy rough surfaces so it will need a grain texture in the diffuse channel, very little spectral highlight because it's old and not shiny at all, and it will need the grain pattern in the bump channel to bring out the roughness.


Where a piece of finished wood like furniture wood, will need a grain texture, with plenty of spectral highlight and reflectivity, and no bump, because it's has a shiny smooth finish.


If the object is to be clear glass the material will need a slight diffused color, some spectral highlight, transparency, refraction, and some reflection.


A basic metal material like a silver spoon, needs a light gray diffused color, some spectral highlight and reflectivity because it's shiny.


There are some basic rule to follow when setting the values of some material channels, to create realistic looking materials. Although there are times these rules need to be broken, for the most part staying close to them or using them as guide lines will usually generate a more realistic looking material.

Diffuse & Ambient: Are the two color channels, when both channels are used their total values added together should not exceed 100%. Example: if the diffuse color is 70%, the ambient color should not go over 30%

Diffuse 100% Ambient 0%

Diffuse 50% Ambient 50%

Diffuse 75% Ambient 25%

Diffuse 100% Ambient 100%

The results of not using the Diffuse & Ambient 100% rule, is the material to bright and shadows washed out.

Transparency & Refection: Most transparent substances have a reflective value, when both channels are used their total values added together should not exceed 100%. Example: if the transparency channel is 60%, the reflective channel should not be over 40%

Transparency 80% Reflectivity 20%

Transparency 80% Reflectivity 100%

The results of not using the Transparency & Refection 100% rule, is the material to bright.

Diffuse & Reflection: When these two channels are used together the reflective value and diffused value added together should not exceed 100%. Or if the ambient channel is used with the diffuse channel, then the reflective, ambient and diffuse channel combined together should not exceed 100% Example: if the diffuse channel is 75%, the reflective channel should not be over 25%. Or if the Diffuse channel is 60% then the reflective and ambient channel combined together should not exceed 40%.
This rule is generally used with metal or plastic type materials, but can also apply to glass or other reflective surfaces.

Diffuse 75% Reflectivity 25% Ambient 0%

Diffuse 100% Reflectivity 75% Ambient 0%

Diffuse 50% Reflectivity 25% Ambient 25%

Diffuse 50% Reflectivity 50% Ambient 50%

The results of not using the Diffuse & Refection 100% rule, is the reflective areas on the material being to bright.

Refraction: In Amorphium a value of 1.000 refraction is the equivalent to air ( no refraction, default setting ). A value of 1.120 is the equivalent to water. A value of 1.330 is the equivalent to glass. Higher values, will represent denser substances such as crystal and diamond. These setting may not be anatomically correct, but they are close enough for general purposes.

Refraction 1.000 Air

Refraction 1.120 water

Refraction 1.1330 Glass

Refraction 1.450

Refraction 1.600

For some instances the rule should be broken one example is for glowing object like the fire on a cigarette or a LED power light on electrical equipment.


Another instance is when transparency maps are used in the transparent channel to specify specifically where transparency will occur. When trans maps are used the transparency channel will usually be turned up to 100%, and will effect the black areas so they are 100% transparent. So the other areas that are on the white areas of the map can have a reflective value, because the transparent and refection do not occur at the same locations on the object, like the vent in this example.


Some type of materials can not really be created effectively in Amorphium, like volume materials. Although Amorphium has a smoke volume object, it can't be used effectively for something like a cigarette smoke stream. Using texture and transparency maps, volume type materials like smoke or fire can be faked.


Layering Elements

Amorphium's material channels are not limited to using only one element to drive the channel. Most all the shaders support two or more color options, which can host a color, texture, shader, or any of the elements provided on the element menu. When using other elements in the color options of shaders, it is referred to as layering, because the elements are being stacked on to one another as layers. When doing so there is virtually an unlimited number of combinations which can be used to create the elements that drive the material channel.

Here is an example of a layered material in the diffuse channel. The Checkerboard and Cell shaders were used, below is a material tree showing how the shaders are layered.



This is how the material is layered. In the diffuse channel the Checkerboard shader is used.


In color one of the checkerboard, the Cell shader is used.


In color one of the Cell shader, black is used to create the black lines, with the edge width adjusted to match up with the Checkerboard line width.


In Color 2 of the Cell Shader another cell shader is used.

In this Cell shader color one is set with a light color for the lines, and the edge width is raised. Color two uses a darker version of the same color.


For the Checkerboard shader color two, it mimics Checkerboard shader color one but with two different colors in the final Cell shader.


In color one of the Cell shader, black is used to create the black lines, with the edge width adjusted to match up with the Checkerboard line width.


In Color 2 of the Cell Shader another cell shader is used.

In this Cell shader color one is set with a light color for the lines, and the edge width is raised. Color two uses a darker version of the same color.


Animating

Material channels properties can not be animated, but some of the elements used in the channels can. Paint can be animated, so by using color, shaders or texture maps to color the objects, the paint element is left open to use as an alpha, in the alpha driven channels, Specular Roughness, Transparency, Refraction, Reflectivity or even Bump.

Here is an animation that uses paint going from black to white, in the Refraction channel.


Using paint to drive the Ambient color channel.


Using paint to drive the Specular Roughness channel.


Using paint to drive the Transparency channel.


Using paint to drive the Refection channel.


Using paint to drive the Bump channel.


Using the Time and Mixer shader, an object can alternate the material used in an animation.

This is the layering of the time animation.




This interface tutorial is written and provided by : Stephen Ray