Chapter 1 AL Working in 3D RI The initial impulse for someone interested in learning 3D graphics is D MA TE to immediately jump in and start building—trust me, I have been there! While there is definitely something good to be said about diving right in, if you spend a little time creating a foundation of skills, you will have less need to break bad habits later.
■ Chapter 1: Working in 3D Understanding 3D Space Figure 1.1 Three dimensions from a screen perspective Maneuvering in 3D space can seem easy at first glance. After all, only one dimension has been added to the standard page layout, and that dimension is what we experience as we move around every day. However, believe it or not, the addition of this dimension can make navigation harder to get used to for the novice 3D artist.
Understanding 3D Space ■ 3 Figure 1.2 Three dimensions from a map perspective Luxology’s modo and many other common 3D applications work by default with the y-axis pointing up. Some applications, however, use z as the up-axis. The modo program allows you to customize this aspect in its preferences. Choose System ➔ Preferences ➔ Input ➔ Accuracy And Units. From the heading marked Coordinate System, you can change the upaxis to z, y, or even x to suit your needs.
■ Chapter 1: Working in 3D option without changing the scene in any way, but it is important to note that both camera and light perspectives are tied to actual objects in 3D space. Thus, if you move these views, you will actually be moving (or rotating) objects and changing the makeup of the scene. Movement in camera and light perspectives can be reversed with the Undo command, but movement in the generic perspective view cannot be undone.
Exploring a 3D Scene A simple triangle represents the polygon at its most basic level. Three points (with three edges connecting them) creates a defined surface. For the most part, four-sided polygons, also known as quads, will be the basis for your models. The reason for this will become clear when modeling is discussed in the coming chapters, but suffice it to say that many forms can be more easily defined by quads than by triangles.
■ Chapter 1: Working in 3D Figure 1.3 A few examples of possible textures Lights There are two methods of adding light to your 3D scenes: using computer representations of real lights (standard lighting) or casting light from the environment and textures in the scene (radiosity). The former is relatively easy to compute and delivers results more quickly. The latter uses more-complex computation and slows the finished image but results in lighting with more subtlety, nuance, and realism. Figure 1.
Navigating the modo User Interface Traditional lights in 3D space use simple math to add brightness based on an area of influence, light color, and intensity. These lights come in common variations that are seen in most 3D applications. Distant lights (sometimes called directional lights) are similar to the sun. The actual light comes from infinitely far away and is adjusted by the angle it enters the scene. Spotlights simulate their real-world namesake.
■ Chapter 1: Working in 3D (red for x, green for y, and blue for z). These same colors will appear in tool handles after modeling begins. In the perspective view, indicators are displayed for all three axes. As in the orthographic view, each line indicates the positive direction. In the perspective view, there is also a light gray square that aligns itself to the two axes that are most perpendicular to the current view.
Maneuvering in 3D Space Figure 1.6 The modo user interface 4 6 4 1 2 5 3 5 3 4 4 1 3 1 5 1 - Orthographic Viewport 2 - Perspective Viewport 3 - Axis Widget 3 5 4 - Navigation Widgets 5 - Scene Information (Grid Size on Bottom) 6 - Object Manipulation (Transform) Tools Maneuvering in 3D Space Now that you have a basic understanding of our canvas, you are ready to start maneuvering the viewports to get the best view for any part of the creative process.
■ Chapter 1: Working in 3D zoom to fill the view after the mouse button is released. Finally, you can zoom with the scroll wheel. This last option is also context sensitive and will zoom toward the cursor position. While in the camera view, using the Alt+Ctrl / Option+Control key combo with the right mouse button adjusts the focal length of the camera and enables you to zoom in and out, as opposed to actually moving the camera in and out in space. The real complication comes with rotation.
Maneuvering in 3D Space ■ 11 Figure 1.8 Perspective view of a model First, let’s look at the rotation based on the center. This type of rotation is accessed by pressing the Alt/Option key while clicking the left mouse button, or by clicking and dragging the rotation widget in the top-right corner of the viewport. As you drag up, down, left, and right, the view shifts around the focal point.
■ Chapter 1: Working in 3D Finally, by holding Alt/Option and using the middle mouse button (or scroll wheel button), the view can spin perpendicular to the viewport. This can be useful if the current view is upside-down and needs to be flipped over quickly. This is also useful when aligning a view that is slightly skewed and requires a minor rotation to see a level view of the scene. The three movement tools work well when the view is focused on either your entire scene or a specific selection.
Maneuvering in 3D Space ■ 13 Figure 1.9 Starting perspective Figure 1.10 Goal after navigating the perspective view If a value is entered in a numeric field, holding the Ctrl / Control key and pressing the Enter key (on the Mac, Tab or Enter) will change the other values proportionally. In other words, if all fields read 100% for scale and you enter 10% in the X value, the other two values will be changed to 10% automatically.
■ Chapter 1: Working in 3D First, let’s consider the Move tool. When activated, the tool handles appear at the center of the selection and show arrows that align to each axis (x, y, and z) and circles that float between the arrows in free space. For reference, the colors of the arrows correspond to the axis of movement. To move in a single axis, click and drag on the individual arrows. When the axis is active, the arrow turns yellow.
Maneuvering in 3D Space by the ends of the tool handles, which are boxes instead of arrows. Just as on the Move tool, the handles scale in one direction, and the circles scale in two directions (one plane). Clicking off the handles scales based on the work plane. Because clicking in open space still scales the object independently, it is usually preferable to use the planar circles and scale uniformly in two directions.
■ Chapter 1: Working in 3D 2. Select a layer either by clicking on it in a viewport or by clicking on it in the Items list tab on the upper-right side of the screen. 3. To move more than one layer at a time, Shift+click on it in the item list. Figure 1.11 4. Use combinations of the Move, Rotate, Scale, and Transform tools to get the cubes into the positions shown in Figure 1.11.
Review • W = Move tool • E = Rotate tool • R = Scale tool • Y = Transform tool In the next chapter, you will start creating 3D objects. You will look at object primitives and all of their options that enable you to control their size proportions and structure. This will also give you the opportunity to explore some additional sections of the modo user interface. On the DVD for this chapter are practice files and videos covering the topics discussed in the previous pages.