2. Lecture Topics
• The Cartesian Coordinate System
• Types of 3d Modeling Suites
• Orientation of "Normals"
• Breakdown of Model Parts
• Comparison of 3d File Types
• Imaging Terminology
• Comparison of Image File Types
• Rendering - In Brief
• For next Class...
3. Cartesian Coordinate System
• This is the coordinate system
that SketchUp, and in fact most
modeling suites are based
around.
• The axes used in SketchUp are
as follows:
o X (Red)
o Y (Green)
o Z (Blue)
4. Types of Modelers
• Polygon Mesh Modeling
o Models consist of surfaces that
are comprised of polygonal
faces. Vertices define the
endpoints of line segments, and
segments define the edges of
polygons.
o SketchUp, 3DS Max, and
Cinema 4D are all examples of
polygon mesh modeling suites,
although SketchUp's methods
are somewhat hybridized.
5. Types of Modelers
• NURBS - Non-uniform Rational
B-Splines
o Models consist of surfaces that are
comprised of mathematically
calculated curves.
o Rhino & Autodesk Maya are two
suites that use NURBS heavily, and
very well. Example:B-splines are defined by
the mathematical average of
o SketchUp does NOT support true control points (green), whose
NURBS, but plugins are continually "weight" pulls the spline into
position (blue).
adding new features that are similar.
6. Normal Orientations
• An important concept to understand about 3d
modeling is the idea of "surface normals".
• Surface normals are represented as a vector
pointing perpendicularly outward from a
surface, as represented by the diagram to the
right.
• Proper orientation of surface normals allow for
models to correctly display textures and
material properties, and are therefore critical
for good modeling technique.
A surface normal, whose
• We'll cover orientation in SketchUp once we orientation is represented by
the blue arrow.
start modeling, but being aware of it is critical
from the beginning.
7. Polygon Meshes
•
•
Vertex - Individual points that define the endpoints of edges.
•
Edges - Individual lines that define the boundaries of faces.
•
Faces - Individual flat faces make up larger polygons/surfaces.
Polygons - Polygons are made up of multiple flat faces, and are treated as
•
one.
Surfaces - Larger groups of polygons are treated as one single surface.
8. 3d File Terminology
• .skp - Native SketchUp File Type
o This is the file type we'll be encountering the most. It's the default type
that utilized by SketchUp, and is capable of being imported/used in
other software types.
o This format not only stores geometry and textures, but often contains
other file definitions (trees, cars, etc.), so that it does not require any
additional files if moved. Consequently, these files can get very large if
careful techniques are not observed, but can be very helpful if they
are.
• .dwg/.dxf - Autodesk Drawing/Exchange Format
o Autodesk's .dwg/.dxf are currently the most popular format for bringing
in architectural and product design objects in SketchUp. These often,
however, require significant cleanup for proper use, and should only
be used as reference.
9. 3d File Terminology
• .obj - Wavefront 3d object file
o Now the most widely accepted archival file type, these models are
contain information about both a models geometry and texture setups,
and therefore are normally easy to set up and work with as long as
they have been set up to certain specifications.
o This file type is more popular because it is a text/plain file type. This
means that more of the geometry is readable by the computer, and
therefore is easier to work with. If you were to open this file, it includes
text and english characters.
• .3ds - 3D Studio Max
o This file type was the original file type of the 3d modeling software of
the same name.
o The .3ds file type is less popular because it is a binary file, meaning it
consists of 0's and 1's. This limits the amount of geometry the file can
contain to 65,536 vertices. As you can imagine, this limitation puts a
rather significant handicap on the file type.
10. Image Terminology
• Raster Graphics
o These types of images (often
referred to a bitmaps in
general) are based on pixels,
and are not infinitely scalable.
They are created by digital
cameras, and by softwares
like Adobe Photoshop and
GIMP.
• Vector Graphics
o These types of images are
used in web graphics, and
are infinitely scalable without
loss of quality. They are
created with softwares as
Adobe Illustrator and
Inkscape.
11. Image File Types
• .jpg - Joint Photographic Experts Group
o Now an actual file type, this was originally the name of the
compression applied to pictures. This image type is normally referred
to as a "lossy" format, which means that once this compression is
applied, quality is lost, and the action cannot be reversed.
o These are the most common image types we'll be dealing with, but
due to their lossy nature, I'll be teaching you how to work with them so
as not to lose detail, but maintain a reasonable file size.
• .png - Portable Network Graphic
o This file type can grant several significant bonuses over .jpg if used
properly, including "lossless" compression.
o These image types also support a feature called alpha channel
transparency, which allows an image to have a transparent
background, removing the need to cut out backgrounds in photoshop,
or mask out areas of photographs or textures. We'll cover alpha
channels in more depth later on in class.
12. Image Terminology
• .tiff - Tagged Image File Format
o .tiffs are a commonly used archival format for 2d graphics due to their
support of both lossy and lossless information, as well as the ability to
store other types of images inside the .tiff. This ability can also result
in .tiff images being very large.
o .tiff can store both raster and vector images, and are capable of
working with layers.
• .bmp - Bitmap Digital Image
o Another type of pixel based image whose capabilities vary based on
its individual properties, mostly something called Bit-depth.
o We'll cover bit-depth more in later classes, but know that depending
on their bit depth, bit maps must either store their alpha separately or
embedded within the file.
13. For Saturday, Feb. 9th
• Be ready to ask questions on any of the previous slides or topics should
you have them.
• Make sure you install the TSCC Codec on your personal computer to allow
you to watch the class lectures or videos again should you wish to. We'll
be starting to speed up from here with terms, concepts, and how to
execute them, so you'll want to review frequently to keep up and retain the
info.
