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.

Guidelines:

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

Detail

Even simple objects have more to them than first meets the eye. Details make the object richer, more interesting, more Appealing.

Guidelines:

  • Use reference to help you discover what details you might want to add to your objects.

Functionality (sub-catagory of "Detail")

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.

Guidelines:

  • Use reference to help you discover what visual elements communicate how real-world objects function.

Scale & Proportion

Objects/Characters sized and structured appropriately; proportions are based in reality; elements are proportionate to each other.

Guidelines:

  • 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)


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.

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.

Guidelines:

  • 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
    • Pyramid
  • 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

Volvo:
boxy, but good
Batmovile:
fast & dangerous

Exaggeration

Modifying an object element to help communicate an idea.

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.

Guidelines:

  • Sharp, dangerous teeth should be sharper and exposed, too big to fit in the mouth.
  • Curvy, sexy body should be curvier and more defined.
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

 

  • Structural supports have limits
    • 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:
    • 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, Mass, Weight, & Load
    • Force is a measure of the interaction between bodies
    • Mass is a measure of the amount of material in an object
    • Weight is the gravitational force acting on a body
    • Load usually means the force exerted on a surface or body

As you put more bricks onto a table, the load increases as the weight of the bricks spreads out over the surface tabletop. That increases the force on the legs. The structural integrity of the table will be tested as you add more bricks. First the tabletop will bend (depending on the tabletop’s flexibility) where there is the least support (in the middle). Eventually the tabletop will reach a breaking point and (depending on the quality of the material) it will bend, break & fracture - collapsing to the ground.