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<TITLE>3D Graphics Modelling and Rendering mini-HOWTO: Background Information</TITLE>
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<H2><A NAME="Background"></A> <A NAME="s2">2. Background Information</A></H2>
<P>The content of this section exists only to describe, in general, the
three main components required for three-dimensional modelling and
rendering with a Linux-based system.
<H2><A NAME="Background-GL"></A> <A NAME="ss2.1">2.1 The Graphics Library</A>
</H2>
<P>A graphics library consists of the most basic tools used for manipulating
graphical images. Think of all the things needed to build a house: wiring,
plumbing, wood, bricks, and such. The graphics library can be thought of
as not these items, but rather the tools used create such items. After
all, wire, metal tubes, planks, and bricks don't magically appear; rather
they are created and formed as entities unto themselves. On a similar note,
graphics don't magically appear on the screen -- typically they consist
of lower-level graphics primatives (lines, rectangles, and individual
pixels, for example).
<P>So the graphics library, then, can be thought of as the low-level graphics
primatives used to build more complex objects (spheres, boxes, complex
polygons, etc.). Those complex objects are then used to build even more
complicated shapes and figures.
<P>The graphics library installed was the freeware implementation of OpenGL
called <EM>Mesa</EM>.
<H2><A NAME="Background-GM"></A> <A NAME="ss2.2">2.2 The Graphics Modeller</A>
</H2>
<P>Since the graphics renderer is, ideally, completely hidden from the end-user,
we'll deal with that last (besides which, modelling is the next logical step
in keeping with my house-building analogy). However, when it comes to the
actual installation, a graphics modeller relies on the renderer already being
installed.
<P>If the graphics library is akin to the tools used to build the tools used
to build a house (!), then graphics modellers can be thought of as the
tools used to build the blueprints for the house -- sophisticated
blueprints, as modellers let you dictate exactly where the wiring, plumbing,
wood panels, bricks, and forth are supposed to go. Furthermore, they
let you pick the style of panelling and the colour of the bricks you
desire.
<P>The graphics modeller installed was the freeware package called
<EM>The Mops</EM>, which produces <EM>RenderMan</EM>-compatible files.
<H2><A NAME="Background-GR"></A> <A NAME="ss2.3">2.3 The Graphics Renderer</A>
</H2>
<P>In keeping with the house-building analogy, the graphics renderer is then
the construction workers. Once you have the blueprints and materials ready
to go, you need something to actually build the house so it appears how it
was designed. The graphics renderer is given information (i.e., the
blueprints in the form of a <EM>RenderMan</EM>-compatible file, or
equivalent) from the the modeller to produce the final result.
<P>Just as the graphics modeller needs the graphics renderer before it can be
installed, the renderer relies on the graphics library being installed
beforehand.
<P>The graphics renderer installed was the <EM>Blue Moon Rendering Toolkit</EM>
which uses <EM>RenderMan</EM> files.
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