1. Navigating in 3D MAX
Guilford County SciVis
V106.02 part 1

2. Viewing Objects and/or Scenes
Depending upon the
software program, the
image on the monitor
could be a Perspective
view, an orthographic
view, or a combination.

3. Viewing Objects and/or Scenes
 3D Studio Max, Rhinoceros, and some other modeling
programs open with a four window display showing
top, side, and perspective viewports.
 Truespace opens with a single perspective view with
orthographic views available on demand.
 Most programs allow you to fill your display area with
any single viewport or varying multiple combinations
of display windows.

4. Viewing Objects and/or Scenes
 Various veiwports may be
formed by viewing angles.
 The image viewed depends
upon the line of sight of the
viewer.
 To move across a scene is
called panning.
 The scene may be rotated
about any of its three axes: x,
y, and, z.
 Views may be zoomed which
magnifies the image. The size
of the object is not increased.

5. Perspective
 Perspective mimics the way a human eye works and
provides scenes that have a “natural” appearance.
Perspective windows are included in all 3D modeling
programs.

6. Perspective
 In perspective, parallel line
converge at a vanishing
point on the horizon.
Perspective views typically
contain one, two, three
vanishing points. Horizons
may be raised or lowered
to change the vertical
viewing angle.
 In perspective, objects
seem to become smaller as
they move away and larger
as they come closer.

7. Perspective
 Objects seem to become
dimmer as they move
away. Atmospheric
features in the software can
be used to simulate
atmospheric density.
 Perspective viewports can
distort space and “fool the
eye” when trying to
position objects in 3D. It is
not a good idea to attempt
object placement and
alignment using the
perspective window alone.

8. Orthographic (Parallel Projection)
 Orthographic (Parallel Projection) viewports provide
an image in which the line of sight is perpendicular to
the picture plane.
 “Ortho” means straight. In orthographic
projection the projectors extend straight off of the
object, parallel to each other.
 Points on the object’s edges are projected onto a
picture plane where they form line on the plane.
The lines create a 2D image of the 3D object
being viewed.

9. Orthographic (Parallel Projection)
 Typically six different views can
be produced by orthographic
projection:
 Top, bottom, front, back, left,
and right sides.
 Lines and surfaces that are
inclined to the picture plane
appear as fore shortened edges
and surfaces on the plane to
which they are projected.
 Orthographic viewports are
extremely useful in the accurate
alignment and positioning of
objects and features with respect
to other features and objects .

10. Coordinate systems
 Coordinate systems are used to
locate objects in 3D space.
 Lines drawn perpendicular to
each other for the purpose of
measuring transformation are
called the axes.
 In the 2D Cartesian coordinate
system there is a horizontal axis
called the X-axis and a vertical
called the Y-axis.
 In 3D space a third axes is added
called the Z-axis.

11. Coordinate systems
 Where axes intersect is called
the origin. The coordinates
of the origin are 0,0 on the
2D plane and 0,0,0 in 3D
space.
 Numerical location placed
uniformly along the axes are
called the coordinates. These
numbers identify locations in
space. When written or
displayed, numbers are
always given in the order of
X first, then Y, the Z.

12. Coordinate systems
 Axes may be rotated or oriented
differently with in 3D space
depending upon whether you are
working with an individual
object, a viewport, or objects
within a scene.
 Local (user) coordinate system-
assign axes to particular object.
 World (global) coordinate
system-assign axes to the
scene.

13. Coordinate systems
 Many 3D modeling programs allow you to constrain
movement (rotation, scaling, and transformations)
along one axis, two` axes, or three axes.
 For example, you could lock the X- and Y-axes thereby
restricting movement of deformation to only a Z
direction.
 Relative coordinates are used to transform an object
starting at its current position.
 Absolute coordinates are used to transform an object
relative to the origin.

14. End Part I