Main Content
Lesson 3: Solid Object Modeling
3.6. Moving On to Your Own Modeler
Let's recap Part 2 of the video tutorial and, while we're at it, expand a little on the subject of modelers:
- The surface geometry of objects can be defined using polygons. Most surfaces can be resolved into triangles, which have the virtue of being flat—always.
- Solid-object models often begin with primitives, basic 3-D objects like cubes or spheres. A user tells his or her modeling software, "Make me a cube." Presto: That virtual cube is created as a set of eight square surfaces (polygons) at right angles to each other. The user might later ask for each of those eight surfaces to be further subdivided into two triangles each, or into nine smaller squares each. Often, the software will do this automatically when the user initiates some other operation.
- The surfaces of models can be manipulated in different ways depending on the specifications that were used to define those surfaces, such as vertices (points), edges (lines), and faces (polygons).
- Why this emphasis on surfaces? In modeling, objects are typically defined as "what's contained within the surfaces." That tends to be different from how we think in the non-modeling world. In the morning, do you think of a glass of orange juice as "a substance contained within a tapered cylinder?" If you do, you're an engineer. (Okay, sorry, hoary engineer joke here: An optimist sees a glass half full. A pessimist sees the same glass half empty. An engineer sees a glass that is twice as large as it needs to be.)
- Modeling often entails pushing, pulling, resizing, or otherwise manipulating parts of the surface of an object. Sometimes those manipulations correspond to real operations that will actually take place in manufacturing. For example, pushing a circular surface into a metal object might correspond to drilling a hole (a subtractive process) in a manufacturing step. Designing solid objects using a modeler involves more than simply making shapes; it also draws upon knowledge of materials, machining processes, human capabilities, and economics. There's little value in specifying that a hole should be drilled in a place that no real drill bit could actually access.
Pause to Reflect
Is creating a computer model of a video-game character considered engineering? After all, a video-game artist is not designing within the constraints of materials' physical properties or access to a milling machine cutter. But why did these videos emphasize the value of keeping models simple—fewer polygons, for example? (Hint: There are constraints to the operation of a computer. What happens when you try to watch an HD movie on a device with a slow internet connection?).
Roll Up Your Sleeves and Model!
It's time to roll up your sleeves. You could spend the rest of your career learning about modeling by watching videos. Right now, there are over 200 Lynda videos on just the subject of CAD (computer-aided design) using modelers like Autodesk Inventor, AutoCAD, SketchUp, SOLIDWORKS, Rhino, and the like. But we'd rather have you actually model, not just watch videos.
If you followed the instructions at the beginning of this lesson, you've already selected a modeler and installed it, and can now run it on a computer. So do that—spend five to 10 hours familiarizing yourself with your modeler. Most modelers come with free user-friendly tutorials. If those tutorials don't launch automatically when you install your software, do a little research on the company's website, YouTube, or Lynda. Stretch yourself. You're an educator: Create an informal individualized educational plan that is tailored to your interests, current expertise with modeling software, and job responsibilities. Then complete the assignments on each of the next two pages. The assignment on page 3.7 is due this week, while the assignment on page 3.8 is due next week. Have fun!