The document discusses key concepts for working with 3D objects in animation software. It explains that 3D objects use three coordinates (X, Y, Z) to specify the position of vertices in 3D space. It also discusses important 3D modeling concepts like pivot points, vertices, polygons, edges, and faces that make up 3D meshes. The document contrasts adjusting the viewport through panning, zooming, and rotating from directly manipulating the 3D object through transformations, scaling, and rotation.

2.  In basic geometry, students learn to
plot points on a Cartesian plane. This
is named for French mathematician
René Descartes (1596-1650).
 A Cartesian coordinate system
specifies each point using an ordered
pair of coordinates. The first number
indicates the position on the X axis
and second indicates the position on
the Y axis.

3. Cartesian Plane Used
In Basic Geometry

4. Three Coordinates
Per Vertex
 In 3D animation software, each point is referenced with three
numbers that indicate the position on the X, Y, and Z axes.
 The pivot point (registration point) for a 3D object is used to
determine the placement in 3D space.

5. Elements of a
3D Object
 In addition to the pivot point, a
3D model can be broken down to
vertices, polygons, and faces.
 Each vertex (or point) in a 3D
model has three coordinates (X, Y,
and Z). 3D models often have
thousands of vertices.
 Several vertices define a polygon
(also known as a face).
 Several polygons fit together to
make the mesh of a 3D object (or
model).
 The line connecting two adjacent
points is called an edge.

6. Which Way is Up?
Y axis or Z axis?
 There are several different software applications used in the
industry. While there are some major differences, many basic 3D
concepts are common to most software.
 One of the most important differences between different
software is the vertical axis. Some applications name the up and
down axis as Y while others name it Z.
 Because models in one application are sometimes transferred to
a different application, it is important for students to be aware of
this difference.
 Two versions of this slide show have been given (Y-up and the Z-
up). Teachers should use the one that matches the classroom
software.

7. X Axis
 The X axis is used to plot the left or right position of an object.

8. Y Axis
 The Y axis is used to plot the forward or backward position of an object.

9. Z Axis
 The Z axis is used to plot the position of an object above or below the ground
plane.

10. X, Y, and Z Axes

11. The Origin
 The point where the axes intersect is called the origin. In 2D geometry, the
origin is (0,0) but in 3D software the origin is (0,0,0).

12. Orthogonal Views
 The software window that shows the 3D object is commonly
called a viewport.
 The user has the option of setting the viewport to an
orthogonal (or straight-on) view. An orthogonal view could be
a front view, a top view, or a side view.
 An orthogonal view is parallel to the X, Y, or Z axis.

13. Perspective Viewport
 In addition to the orthogonal views, a viewport can be set to a
perspective view. This type of viewport allows the user to
rotate the view in order to see a model from every possible
angle.

14. Customized Viewport
Layouts In most 3D applications, users can customize the arrangement
of the viewports.
 When animating objects, a single viewport is often used. This
single view can easily be changed to an orthogonal view or the
perspective view.
 When modeling objects, a quad arrangement of the viewports is
usually preferred. This allows the user to see the front, top, side,
and perspective views simultaneously.

15. Quad Viewport
Layout

16. Viewport Navigation
Zoom (or Magnify)
 All viewports have a tool which allows the user to zoom in or
zoom out.

17. Viewport Navigation
Pan All viewports have a tool which allows the user to pan left or
right and up or down in the viewport.

18. Viewport Navigation
Orbit (or Rotate) The perspective viewport has a tool which allows the user to
orbit (or rotate) the view.
 The ability to orbit is not available in the orthogonal views
(front, top, side).

19. Rendering Style
 In each viewport, the user may choose from a variety of
rendering styles to view a 3D object.
 The most common styles are wireframe (shows the points and
edges of each polygon), shaded (shows a solid version of the
model), and a shaded with wires (a combination).

20. Viewport Navigation vs
Object Manipulation When beginning to use 3D
software, it is easy to confuse
adjustments to a view with
actual changes to an object.
 Viewports can pan, zoom,
and orbit to give the user the
best possible view while
modeling or animating.
 Objects can be transformed
(moved), scaled, or rotated.
 Viewports
 pan
 zoom
 orbit
 Objects
 transform (move)
 scale
 rotate

21. Transform (Move)
 In the example below, the fish has moved from one position to
another.

22. Scale
 Objects can be scaled (sized) on each axis.
 If the X, Y, and Z axes are all scaled the same amount, the size
of the object will stay in proportion.
 If on axis is scaled a different amount than the others, the
shape of the object will distort.

23. Rotate
 The object can be rotated on each object. This is measured in
degrees with 360°being a complete circle.
 All the most applications refer to the axis that serves as the
center of rotation, the terms heading, pitch, and bank are
sometimes used.

24. Rotation on the Z Axis

25. Rotation on the X Axis

26. Rotation on the Y Axis

27. Pivot Point
 The fish object used throughout this slide show has the pivot point (or
registration point) placed in the middle.
 You can move the pivot point of a 3D object but you should do so before
you begin animating.
 Tires and propellers would need
the pivot point placed perfectly
in the center of the object.
 If you were to create a 3D door
that would open, you would
place the pivot point at the
hinge.
 The pivot point for a golf club or
baseball bat should be placed at
the point where the hands would
be placed.