# Modeling

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```					       3-D Modeling
Designing in the world of 3-D
Sources
   www.prodesktop.net
   http://www.3dcafe.com
   http://www.transvisioninc.com
   http://www.pixar.com
   http://www.tecso.com.pl/flash/flashindex.html
3d Modeling
   Modeling in 3 dimensions is the future of
computer design and animations. This
technology has been available for many
years, however due to the enormous costs to
develop, this technology was out of
affordability range for most companies.

   The uses for 3D design are almost limitless.
Some Common Uses:
   3D development of landmarks even before they are constructed.

   Creating computer animated movies such as Pixar’s toy story.
http://www.pixar.com/shorts/index.html

   Home builders can show a virtual reality tour of homes before they are
built or can show buyers how their home looks with the custom options
they choose.

   Automobile purchasers can see how their car looks with ther selection
of colors, rims, accessories and additional options before they commit

   Industry can utilize 3d modeling programs to show clients perspectives
jobs before completion.
   http://www.tecso.com.pl/flash/flashindex.html
3d Animation
3-D Coordinate Space
   3-D Coordinate Space
   Everything done in a 3d computer application revolves
around the concept of a 3-d coordinate system.
   Imagine yourself (as difficult as it may be to do) at the very center
of the universe. There are six directions ranged about you in
three pairs:
   Left and right--the horizontal or “x” directions.
   Up and down--the vertical or “y” directions.
   Forward and backwards or the “z” directions--for which we have
no general name.
   Because of gravity, up and down have a physical meaning quite
distinct from left and right or forward and backward, however we
must try to throw away our concept of gravity for the use of 3d
modeling.
Boolean Operations
   Boolean Operations are modeling methods that make use of two
objects that overlap and therefore share part of the same space.
   In Boolean union, the geometry of the overlapping area is
eliminated and a single object is created from the two using all of
the exposed surface area. Union is generally used to merge
objects that are most easily built from component parts that have
been modeled separately.
   Boolean subtraction is used to sculpt out the overlapping volume
from one object or the other. After the operation, one object is
left, minus its overlapping region with the other object.
   Boolean intersection preserves the overlapping region only,
eliminating all the rest of both objects.
Boolean Operations Quiz

is each picture?
What type

of operation
Results of Boolean Operations

Boolean Subtraction
Boolean Union

Boolean Intersection
Model
   In the language of 3-D graphics, a model is a
data file that contains the information needed
to view or "render" a 3-D object. This
information includes two types of information:
   1. The geometry--the shape--of the object.
   2. The surface attributes of the object--
meaning data that allows the object to be
properly colored so that it looks like it is made
of some kind of material (e.g. metal, glass,
wood, plastic, etc.)
2 Aspects of Modeling

Geometry

Surface
Attributes:
Varnished Wood
Primitive Solids
   Primitives are the basic 3D geometric shapes that are
automatically generated by 3D modeling applications, and which
therefore need not be constructed from scratch. A very
considerable amount of modeling (perhaps most) begins with
primitives, which are then edited and used with other primitives to
create more complex objects.
   All applications provide spheres, cubes, cylinders (sometimes
called disks) and cones. Some provide a wider array. All
primitives have parameters that define their size and shape. A
sphere necessarily has a center point and a radius, though the
application may also provide for defining the sphere by its x,y
and z extents--in effect defining the sphere by a cube into which
the sphere will fit.
Primitive Solids
Cylinders   Cubes   Prisms/Cones
Rendering
   Rendering is the process of producing images from
a view of 3-D models in a 3-D scene. It is, in effect,
"taking a picture" of the scene. An animation is a
series of such renderings, each with the scene
slightly changed.
   A camera is placed at a location in a 3-D coordinate
space, pointing in a given direction. Those polygons
that fall within the camera's field of view are
mathematically projected onto a plane, just as a real
camera projects an image onto film. The rendering
process necessarily involves some means of
determining whether a given surface of a model is
obscured by another surface closer to the camera.
Rendered Block
Common 3d Modeling
Commands:   Extrusion
   Extrusion is the process of creating three-
dimensional geometry out of flat, two-
dimensional shapes by drawing the 2-D
shape along a path in 3-D space. The
extrusion path may be a straight line or any
kind of curve. If the path is linear, it may be
normal to, or at any other angle to the
extruded shape.
Extrusion
Revolve
   The Revolve command allows you to create a
curved solid from a 2D object by sweeping it
around an axis. Revolve can be used with an
object made from Polygons, Circles, Ellipses,
and Splines. Objects must have a closed
path to be revolved.
Revolve Command

Profile   Axis
Loft Command

   The loft command allows you to create a
solid object by extruding 2 or more shapes
offset at a desired distance from each other.
The shapes may be the same or different to
use the loft command.
Loft Examples
Sweep Command

   A sketch is swept along a defined path to
create a surface or solid. Some important
considerations in sweeps include the relative
location of the sketch to the sweep path and
the curvature of the path. The sweep
command can also be used to create a helix
or a spring type object.
Sweep Examples

Path

Profile

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