3D Modeling Principles
These modeling principles are fundamental standards 3D artists need to think about EVERY time
they sit down to model something. Use of these principles will lead to great looking models.
Realism
Model based on Anatomical, Botanical, Geographical, Structural, or Mechanical Reference; helps
ground the object in reality.
Start by brainstorming your ideas
Research your ideas to find visual reference
Create new sketches showing how the research visuals will be used to build your objects
Guidelines:
Scale & Proportion
Objects/Characters sized and structured appropriately; proportions are based in reality; elements
are proportionate to each other.
Are you using scale & proportion to imply functionality? (doll’s house, giant’s house)
Are you using scale & proportion to exaggerate reality? (Hero vs. Average-Joe)
Are you using scale & proportion to imply weight? (boulder vs. pebble)
Guidelines:
Volume
Objects can be broken down into primitive 3D volumes.
Needed for initial modeling phase, when reducing geometry into low-poly meshes, or when
creating placeholder models. After all, the whole point of 3D is to use DEPTH.
Consider what the overall 2D shape (silhouette) of your object or space.
Circluar
Rectangular
Triangular
Consider the underlying 3D shapes your object or space is made of.
Spheres
Boxes
Cylinders
Pyramids
Guidelines:
•
It is also important to note that the 3 "Basic Forms" (same from any angle) each
have implied values & emotions.
Sphere
Cube
Equilateral Pyramid
soft, round, friendly, cute,
comical, global, sweeping,
unbounded, non-directional
rigid, sturdy, objective,
conservative, conventional,
stuffy, authoritarian, straight
angular, pointy, pokey,
sharp, fast, aggressive,
dangerous, arrow-like,
directional
VW Bug:
cute & friendly
Hummer:
strong and in-charge
Batmovile:
fast & dangerous
Appeal
Good design (not necessarily “cute”); Designed for maximum emotional impact.
See the “Elements and Principles of Design” for more information on how to use (lines, shapes,
color, etc) to visually communicate an idea or mood.
Exaggeration
Modifying an object element to help push the idea you are trying to communicate.
Ultimately, 3D modelers are creating a thing that will have less information than the real-world
object/character. Therefore, you need to emphasize the essential elements of your model that
support what you’re trying to communicate to the viewer.
Sharp, dangerous teeth should be sharper and exposed, too big to fit in the mouth.
Long, sexy legs should be longer and more defined.
Detail
Even simple objects have more to them than first meets the eye. Details make the object richer,
more interesting, more
Appealing.
Use reference to help you discover what details you might want to add to your objects.
Guidelines:
Functionality
All elements of an object or character, even facades or false accoutrements, should appear to have
a purpose, or appear in some way functional (even if the function is decoration). This helps
create the illusion of
Realism
and a sense of curiosity/interest about the object that makes it
Appealing
.
Use reference to help you discover what visual elements communicate how real-world
objects function.
Guidelines:
Weight
All objects have weight. You can create the illusion of weight by how you visibly support the
mass of your object (light & spindly vs. heavy & bulky; top-heavy vs. bottom-heavy, balanced
vs. unbalanced), or by showing how the unsupported mass hangs or spreads out under the force of
gravity.
Scaling properties of bulk matter
Scaling creates a loss of Surface Area to Volume/Mass
•
As an object grows bigger, its volume and mass increase much more rapidly than its
surface area
•
1950s horror movies such as THEM envisioned monster ants, but in fact such scaling
effects prevent insects from becoming very large. For one thing, they don't have
lungs, and have to acquire oxygen through pores in their exoskeletons. Doubling their
size would increase their volume and mass twice as fast as it would increase their
surface area, halving their ability to obtain oxygen for that mass, and at a certain size
a giant insect would simply suffocate.
Compressive Strength
•
A more important scaling issue that rules out giant insects is the issue of
"compressive strength", or the ability of a structural support to bear weight placed on
top of it. The compressive strength of a structural support, such as a column that
holds up a building, is proportional to the cross-sectional area of a slice through the
column. Lightweight insects generally have spindly bodies and legs, while a heavy
elephant needs great massive legs. If an insect were scaled up to large size, it would
simply collapse of its own weight.
These considerations of scale lead back to the notion of strength of materials, which in
turn leads to consideration of how materials are used for building structures.
Concentrated weight needs to be distributed over a wide surface. The taller and heavier
the object, the broader the base needs to be to distribute and support that weight:
Structural supports have limits
Skyscraper: Giant Girder Grids
•
The central support structure of a skyscraper is its
steel skeleton
. Metal beams are
riveted end to end to form vertical
columns
. At each floor level, these vertical
columns are connected to horizontal
girder
beams. Many buildings also have
diagonal beams running between the girders, for extra structural support.
•
In this giant three-dimensional grid -- called the
super structure
-- all the weight in
the building gets transferred directly to the vertical columns. This concentrates the
downward force into the relatively small areas at the building's base. This
concentrated force is then spread out in the
substructure
under the building.
•
In a typical skyscraper substructure, each vertical column sits on a
spread footing
.
(see diagram).
•
This structure expands out lower in the ground, the same way a pyramid expands out
at its base. This distributes the concentrated weight from the columns over a wide
surface. Ultimately, the entire weight of the building rests directly on the hard clay
material under the earth. In very heavy buildings, the base of the spread footings rest
on massive concrete piers that extend down to the earth's
bedrock layer
.
•
One major advantage of the steel skeleton structure is that the outer walls -- called the
curtain wall
-- need only to support their own weight. This lets architects open the
building up as much as they want, in stark contrast to the thick walls in traditional
building construction. In many skyscrapers, especially ones built in the 1950s and
'60s, the curtain walls are made almost entirely of glass, giving the occupants a
spectacular view of their city.
Force
is a measure of the interaction between bodies
Force, Mass, Weight, & Load
Mass
is a measure of the amount of material in an object
Weight
is the gravitational force acting on a body
