Post

Controlling Appearance with Materials

Posted Updated
By CREATE3000
2 min read
Controlling Appearance with Materials

Motivation

The primitive shapes have a default emissive (glowing) white appearance

You can control a shape’s

  • Shading color
  • Glow color
  • Transparency
  • Shininess
  • Ambient intensity

Syntax: Shape

Recall that Shape nodes describe:

  • appearance - color and texture
  • geometry - form, or structure

XML Encoding

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<Shape>
  <!-- appearance ... -->
  <!-- geometry ... -->
</Shape>

Classic VRML Encoding

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Shape {
  appearance ...
  geometry ...
}

Syntax: Appearance

An Appearance node describes overall shape appearance

  • material properties - color, transparency, etc.

XML Encoding

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<Shape>
  <Appearance>
    <!-- material ... -->
  </Appearance>
  <!-- geometry ... -->
</Shape>

Classic VRML Encoding

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Shape {
  appearance Appearance {
    material ...
  }
  geometry ...
}

Syntax: Material

A Material node controls shape material attributes

  • diffuseColor - main shading color
  • emissiveColor - glowing color
  • transparency - opaque or not

XML Encoding

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<Shape>
  <Appearance>
    <Material
        diffuseColor='0.8 0.8 0.8'
        emissiveColor='0.0 0.0 0.0'
        transparency='0.0'/>
  </Appearance>
  <!-- geometry ... -->
</Shape>

Classic VRML Encoding

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Shape {
  appearance Appearance {
    material Material {
      diffuseColor  0.8 0.8 0.8
      emissiveColor 0.0 0.0 0.0
      transparency  0.0
    }
  }
  geometry ...
}

Specifying colors

Colors specify:

  • A mixture of red, green, and blue light
  • Values between 0.0 (none) and 1.0 (lots)
ColorRedGreenBlueResult
White1.01.01.0white
Red1.00.00.0red
Yellow1.01.00.0yellow
Cyan0.01.01.0cyan
Brown0.50.20brown

Syntax: Material

A Material node also controls shape shininess

  • specularColor - highlightcolor
  • shininess - highlightsize
  • ambientIntensity - ambient lighting effects

A sample world using appearance

XML Encoding

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<Shape>
  <Appearance>
    <Material
        diffuseColor='0.2 0.2 0.2'
        emissiveColor='0.0 0.0 0.8'
        transparency='0.25'/>
  </Appearance>
  <Box
      size='2.0 4.0 0.3'/>
</Shape>
<!-- ... -->

Classic VRML Encoding

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Shape {
  appearance Appearance {
    material Material {
      diffuseColor  0.2 0.2 0.2
      emissiveColor 0.0 0.0 0.8
      transparency  0.25
    }
  }
  geometry Box {
    size 2.0 4.0 0.3
  }
}
...

Example

Box 1

Summary

The Appearance node controls overall shape appearance

The Material node controls overall material properties including:

  • Shading color
  • Glow color
  • Transparency
  • Shininess
  • Ambient intensity
Tutorials
Controlling Appearance Materials
This post is licensed under CC BY 4.0 by the author.

Shapes, Geometry, and Appearance