Chapter 1

Exploring 3D Design

IN THIS CHAPTER

Discovering basic concepts of 3D design

Understanding 3D models

Looking at the 3D modeling process

Comparing 3D and 2D methods

In this chapter, you discover all things 3D so that you can understand the basic terminology and concepts of the 3D universe before you go rushing off to the world of Tinkercad.

What Is 3D Modeling?

3D is the abbreviation for 3-dimensional. In the world of Computer Aided Design (CAD), 3D modeling (also known as three-dimensional modeling) is the process or workflow of developing a computer-based (mathematical) model of any surface of an object, regardless of whether it's inanimate (such as a gear wheel) or living (such as an animal or a human being).

3D modeling is done in three dimensions via specialized software and, in your case, Tinkercad. The end product is normally called a 3D model. Someone who works with 3D models may often be referred to as a 3D artist.

The 3D model has the advantage that it can be displayed on the computer screen as a two-dimensional image through a process called 3D rendering. For example, these images are often the uber-cool pictures you see in an architect's slideshow of a new building or house he designed. They also may be used in a computer simulation of physical phenomena, such as virtual prototype testing to see whether the lighting makes a new product desirable to a given market.

The iPhone is a typical example where lighting is an important facet of the design to highlight all the lovely curves and bevels on the iPhone case. (Can you tell I'm an Apple fan?) The model can also be physically created using 3D printing devices, which is where Tinkercad comes into its own, with the ability to export 3D model files for 3D printing.

3D models may be created automatically or manually. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts, such as sculpting. Now that does sound complicated, right? It's not. The Tinkercad interface simplifies the manual 3D workflow, allowing you, the Tinkercad user, to manually create your 3D designs and take them all the way to 3D printing.

Tinkercad is classed as 3D modeling software, which is a class of 3D computer graphics software used to produce 3D models. Individual programs of this class are called modeling applications or modelers. Tinkercad is one of several 3D modeling applications or modelers that are provided by the San Francisco-based software company, Autodesk.

Figure 1-1 shows a typical example of 3D design.

Credit: ESO/ERIS Phase A Team

FIGURE 1-1: The ERIS high-resolution camera and spectrograph concept design for ESO's Very Large Telescope.

3D MODELING IN THE REAL WORLD

As technology and computer hardware have moved forward and become much faster and much more capable, 3D models are now widely used anywhere in 3D graphics and CAD. Their use predates the widespread use of 3D graphics on personal computers nowadays, and many computer games used prerendered images of 3D models as sprites (not the soft drink) before computers could render them in real-time.

Today, 3D models are used in a diverse variety of fields:

• The medical industry uses detailed models of organs, which are created with multiple two-dimensional (2D) image slices from an MRI or CT scan.
• The movie and television industry uses them as characters and objects for animated and real-life motion pictures in film and television (think Avatar, Star Wars, and Game of Thrones).
• The video game industry uses them as assets for computer and video games. If you've used an Xbox, a PlayStation 4, or a Nintendo, you've used 3D assets in the games you've played, regardless of how cartoony or real-life they are.
• The science industry sector uses them as highly detailed models of chemical compounds, such as the human genome project.
• The architecture and construction industry uses them instead of traditional, physical architectural models to demonstrate proposed buildings and landscapes. However, some of those 3D models then become 3D printed models to show the new building or landscape in place in a city environment, for example.
• The engineering community uses them for the design of new devices, vehicles, and structures, as well as a host of other uses, such as nondestructive prototyping.
• In recent decades, the earth science community has started to construct 3D geological models as a standard practice. City modeling is now common practice within government departments in an effort to become more environmentally sustainable with the study of light and wind to create a more "green" world in which to live.

3D models can also be the basis for physical devices that are built with 3D printers or CNC machines.

Comparing 3D to 2D Methods

3D photorealistic effects achieved without wireframe modeling can be hard to distinguish when in their final form. Some of the software available has incredibly sophisticated filters that you can apply to 2D vector graphics or 2D raster graphics on transparent layers, making the finished image look remarkably realistic.

However, wireframe 3D modeling has several advantages over the 2D method:

• Flexibility: The ability to change angles or animate images with quicker rendering, because a realistic 3D model is already there to be used.
• Easy rendering: The automatic calculation and rendering is easier as the 3D modeler has built-in algorithms to render realistically rather than mentally visualizing or estimating the rendered image.
• Accurate photorealism: You have less chance of overdoing, misplacing, or forgetting to include any visual effects.

So, what disadvantages are there to 3D?

• Software learning curve: Learning 3D software can take longer as 3D modelers tend to be more sophisticated and have more "under the hood."
• Difficulty achieving certain photorealistic effects: You can achieve some photorealistic effects with special rendering filters included in the modeling software and specific to a 3D modeler. 3D artists sometimes use a combination of 3D modelers, following that up with 2D editing of the 2D computer-rendered images from the 3D model.

3D modeling makes sense if you're going to fabricate or manufacture your design. It provides a real-world model that can be viewed from any angle,3D printed in order for it to be visualized for real, and even submitted for nondestructive testing (such as the outer casing for a cell phone such as the iPhone, for example).

2D, on the other hand, is great for conceptual work. There is no need for full visualization because 2D is great for approximating what a model might look like with no need for a full 3D model to be created, thus saving on time, training, and costs.

Discovering Model Representation

A 3D model is represented either as a full solid or a shell of a solid. Imagine an old-fashioned wooden toy block as compared to a hollow LegoT brick. Pretty much all 3D models fall into one of two categories:

• Solid: These models define the volume of the object or entity they represent (like a cube, for example). Solid models are often used for engineering and medical applications and are usually built with constructive solid geometry. In this book, I show you how Tinkercad utilizes solids to make your life easier as you design.
• Shell/boundary: These models represent the surface of an object or entity. The boundary of the object is a bit like an eggshell and forms the object's shell, which is infinitesimally thin. Almost all visual models used in games and film are shell models, with surface properties applied.

Solid and shell modeling can create functionally identical objects, such as the Utah teapot, which is one of the most common models used in 3D graphics education (see Figure 1-2).

Credit: Dhatfield/CC BY-SA 3.0.

FIGURE 1-2: A modern rendering of the iconic Utah teapot model developed by Martin Newell (1975).

The differences between solid and shell modeling are the different methods in which they're created and edited in the various 3D modelers that are used, along with differing conventions of use in various fields.

Another difference is in the types of approximations between the model and reality, such as units of measurement and how the solids, shells, and boundaries are represented.

Looking at the Modeling Process

Imagine a big, infinite space, such as a galaxy in Star Wars. Your 3D models represent a physical object, such as a building, a gear cog, or even a nut or a bolt, by using a collection of points in that infinite 3D space (galaxy). You can connect these points using various geometric entities, such as triangles, lines, and curved surfaces.

Because the 3D model is formed by a collection of data (points and other information), you can create these 3D models by hand (manually), algorithmically (procedural modeling), or scanned (using 3D scanning methods).

You can further define their surfaces with texture mapping, which adds physical material...