Basic Rendering Techniques

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Basic Rendering Techniques

• V106.03 Recognizing basic rendering techniques

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Rendering and Shading Techniques

• Rendering produces a finished image.
• The closer the rendering is to create a natural
  scene, the more complex it is, and the longer it
  takes to render the scene.
• Rendering the scene to a file may include such
  things as the background, output size,
  compression, file type, and output path.
• Rendering previews are small and quick to check
  your scene prior to doing a full render.

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Texture Mapping

• The term texture in 3D computer graphics refers
  to image patterns rather than the feel of
  materials.
• The most basic type of texture is a 2D picture
  (often saved as a .jpeg, .bmp, or .tga file),
  which is applied to an object.

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Texture Mapping

• Surfaces may have single colors or they may have
  multiple color patterns, which are commonly
  referred to as textures.
• For example wood has a characteristic appearance
  because of its varying color patterns.
• Even materials like metals which seen to be one
  color, when closely examined, reveal varying
  shades and colors mixed in random patterns.

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Texture Mapping

• Opacity maps control whether a material is
  opaque, transparent, or translucent.
• Adding textures to the object is an extremely
  important part of making objects look real.

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Texture Mapping

• Textures may be acquired in different ways.
• Most 3D programs come with libraries where you
  can select various materials and patterns.
• Typically, 3D programs allow materials to be
  added to the library

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Acquiring Materials

• New materials can be made by combining existing
  library selections and sometimes using mixing
  formulas (blending) provided by other 3D artist.
• There are graphic programs designed for creating
  2D textures (such as CorelDraw or Photoshop) that
  can be found on the Internet or through software
  suppliers.

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UV Space

• UV mapping is a way of trying to solve the
  distortion problems that occur when applying
  image maps (textures) to complex surfaces.
• Many 3D graphic programs allow texture image
  scaling and placement controls.

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UV Space

• U represents the horizontal component of an
  image. It corresponds to the X axis dimension in
  2D coordinate space.
• V represents the vertical component of an image.
  It corresponds to the Y axis dimension in 2D
  coordinate space.
• W represents the z axis in 3D coordinate space.

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UV Space

• By applying UV scaling and placement restraints,
  the most appropriate fit of the image can be
  obtained.
• By manipulating UV controls, it is also possible
  to apply textures to parts of surfaces as well as
  an entire surface.
• Tiling allows pattern to be repeated, much like
  tiles on a floor.

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Bump Mapping

• Bump maps simulate the roughness of surfaces even
  though the surfaces are perfectly flat.
• Bump maps make an object appear to have a bumpy
  or irregular surface. This is possible because
  of higher areas are light and lower areas are
  dark.
• Surface roughness might include the unevenness of
  a brick surface, the weave of a fabric, or the
  bumpiness of an orange.

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Bump Mapping

• The process of creating artificial roughness
  takes less computing power than actually dividing
  the surface into large numbers of polygons and
  moving the vertices of those polygons up or down
  to create a real roughness.
• Settings allow the user to determining the height
  and depth of bumps.
• Bump maps can be produced by photographing
  surfaces, scanning images and actual materials,
  or by using software programs to draw patterns in
  grayscale.

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Lighting

• 3D programs have some type of default lighting,
  which can be changed to create a more realistic
  appearance.
• There are several common types of CG (computer
  graphics) lights.

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The End