Wiley | 978-1-1180-0421-0 | Datasheet | Wiley 3D for Graphic Designers

Wiley 3D for Graphic Designers
Chapter 1
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Working in 3D
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The initial impulse for someone interested in learning 3D graphics is
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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. Before you
start creating anything, you need to understand the canvas you will be working with and
the elements that will be used in the creative process.
This chapter covers the following:
Understanding 3D space
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Exploring a 3D scene
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Navigating the modo user interface and its viewports
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Maneuvering views and objects in space
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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. If you don’t grasp
some foundational principles from the outset, you can become disoriented and lose track
of your model and scene. The addition of a third dimension adds much more than just
another arrow on the monitor.
A standard page layout has two axes: x and y. If these equate to the horizontal and
vertical directions, respectively, then the third axis (z) extends off the screen, toward the
viewer (see Figure 1.1).
This works well for starters, but let’s take it a step further and look at space in terms of
a map or other top-down design. In this case, the plane defined by the x and z axes makes
up the Cartesian plane. More specifically, the negative z-axis is north, and the negative
x-axis is west, in relation to the middle of our workspace (see Figure 1.2).
The center of space (called the origin) will be the starting point for all of our design
work unless we specifically need to work in a different area of the scene. Even in this case,
it is often best to create an object at the origin and then move it to the desired location,
because this will enable you to work with symmetry, easily locate objects, and move the
mesh layer, which can then be reset or animated much more easily.
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.
You can view a 3D scene through either an orthographic or a perspective view. An
orthographic view offers a completely flat vantage point of objects, and placement without
perspective of any kind. This means that objects located farther from the viewer will not
appear smaller as the distance increases. An orthographic view is similar to a floor plan
or elevation in architecture. Because it lacks the distortion associated with perspective,
this type of view is ideal for creating and aligning objects.
Modo offers different interface layouts under its viewport tabs. Model Quad gives us
three orthographic views and one perspective view. Although these two-dimensional
views are initially set to Top, Front, and Right views, they can be changed to any other
angle (Bottom, Left, or Back) and to views that include three-dimensional perspective.
Perspective views enable you to see objects and scenes with real depth. There are
options to use an arbitrary perspective (the default in the Model Quad layout), camera
perspective (based on the default scene camera or any additional cameras that have been
added in the creative process), or light perspective. You can completely adjust the first
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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.
A common analogy is that if an Adobe Photoshop (or other 2D graphic) image is like a
painting, a 3D document is like a sculpture. Two-dimensional art forms (digital and analog) use space, form, and color to create the finished image. Depth and dimension are created through color variation for simulation of light and shadow. Three-dimensional art
adds volume to the mix, which offers more-concrete simulation of real light and shadow.
Because 3D provides added levels of realism, you need to consider additional parts of the
creative process in order to create compelling 3D art.
Exploring a 3D Scene
The next things to consider when beginning to work in 3D are the individual pieces of
a 3D scene and the steps in the creative process that will result in a finished project (a
model, still image, animation, and so forth). This space is filled with points, edges, and
polygons that create the objects. Materials and textures control the appearance of objects.
Lights add shading and highlights to the scene. The camera provides the vantage point for
the finished scene. Let’s look at each of these in more depth.
Points, Edges, and Polygons
At the heart of any model that you will create are three basic elements: points (also called
vertices), edges, and polygons. Points represent a single location in space. The initial
impulse is often to think of these as being analogous to pixels in a raster image, but this is
not the case. Because a vertex represents a single point in space, it is infinitesimally small
and therefore does not appear in a finished 3D render. The fact that the vertex is the basic
building block of the 3D creative process means that it is visible only when several are
combined to create edges and polygons.
Edges make up the next level in the 3D food chain. When two points are joined
together, an edge is created. This edge now exists in one dimension and is still invisible
to the finished rendering. Once again, this should not be confused with a line in a 2D
image file. For both edges and points, it is better to consider a vector illustration without
any line weight assigned. Individual points and lines may appear on the page, but they
will not print unless some thickness is attached to these elements. To see these elements,
you must have a combination of at least three of them (points and edges), which creates a
polygon.
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. By combining and blending
together multiple polygons, objects take form.
S i n g l e - S i d e d P o lyg o n s
Polygons exist as two-dimensional elements within the three dimensions of a scene. The flat
surfaces of polygons face in a single direction. Just as the points are infinitesimally small, so
polygons are infinitely thin. This means that they are invisible when viewed from the back.
Some thickness must be added in order to make the geometry appear from all angles.
Materials and Textures
After polygons are created, they must be assigned surface attributes to define their
appearance. A material contains the basic description of how light interacts with a surface. The key components of a material are color, reflection, transparency, refraction,
absorption, and emission of light. A material creates these attributes at a very basic
level that is defined by either a color or a percentage (depending on the attribute). Proper
combination of these properties can create a wide variety of looks and styles. To achieve
something beyond the evenly distributed appearance of a basic material, additional layers
must be added.
Textures add additional detail to surfaces. Textures are made from either rasterized 2D
images or mathematical functions that display colors based on various inputs. Images can
be placed on the surface of 3D models and offer a high degree of customization. You can
place details exactly where you want them and edit them either by using an application such
as Photoshop or by using texture painting inside of modo. The downside of image textures
is that they can become pixilated if they are not of a high-enough resolution. Mathematical
textures (known as procedural textures) are free from resolution and have a fairly wide
range of styles, from simple grids and gradients to complex fractal algorithms. These textures, however, cannot be edited directly, so placement of detail is random.
These textures can be used to modulate any aspect of a material. Color can be applied
to add variation as well as to colorize reflections or transparent tints. Other possibilities
include changing the amount of reflection or transparency, the shininess, the translucency, or even adding the appearance of depth on a surface (see Figure 1.3).
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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 1.4 shows a simple
scene with standard lighting, and Figure 1.5 shows that same scene using radiosity.
Figure 1.4
Figure 1.5
A scene using standard 3D lights
A scene using radiosity for lighting
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. Point lights are
similar to lightbulbs and cast light outward from a single point, in all directions evenly.
Area lights are similar to soft boxes used in studios. Other lights are more situational
and are covered in depth (along with the other lights mentioned here) in the following
chapters.
Radiosity is also known as global illumination, because illumination comes from other
angles than just the direct light source. In this lighting model, light is based on light
particles (known as samples), which project into a scene much like real-world light. As
with light particles in the real world, these samples can bounce off surfaces to provide
illumination in areas where a light does not have a direct effect. Each bounce of light adds
an order of complexity to the calculation and, as a result, causes a slower render time.
Because light samples are blended together for the final result, using more of them creates
a smoother finished look and (like other quality-improving options) slows the final image
production.
In general, a combination of both lighting types gives the best quality and control.
However, there are times when using just one or the other can deliver excellent results.
The Camera
The camera in a 3D scene gives the viewpoint for finished images. Cameras appear only
as representations in the scene and will not appear when a finished image is rendered
(so you don’t have to worry about them showing up in reflections). Cameras offer control
over many of the options that physical cameras have. You can control focal length, lens
distortion, f-stop, film back, and shutter speed. Although they are simple, cameras are
the window into a scene, so using them properly will improve your art and add impact to
your designs.
Navigating the modo User Interface
Modo offers visual cues that enable us to keep things straight from an orientation standpoint. In the bottom-left corner of each viewport window, a small axis indicator shows,
in the orthographic view, the two axes making up the plane of view. The colored lines
point in the positive direction, and the colors always correspond to a particular direction
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(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. This square indicates the orientation of the work plane, which
is presented in more depth in Chapter 2, “Creating Objects.” By staying aware of these
markers, we can more easily keep the scene aligned.
In addition to the axis widget, the perspective view offers a gradient background that
helps to keep us from looking at our scene upside-down (or enables us to more easily get
there if that is our desire). The background consists of a two-color gradient: a light bluegray color indicates up, in the positive y direction (think of the sky); and a darker shade of
the bluish color fills the negative y direction (indicating the ground). Because we spend a
lot of time rotating around our objects to get the best view, staying aware of this gradient
ensures that we keep our feet on the ground, so to speak.
Before you move on to navigating this space, you need to know about scale. You
may notice that there are no document boundaries in 3D space as there are in a page
layout document, at least not visible ones. What we do have to consider is the depth
that the computer is able to re-create. This is called draw distance. A good example of
a short draw distance can be seen in older racing video games. As you drive along a
course and look into the distance, objects (such as buildings, trees, and mountains) will
appear rather suddenly instead of growing from small points on the horizon. Although
modern 3D applications are much more capable of handling distance than those games
were, we want to keep draw distance in mind and create our scenes at (or near) actual
scale.
In the bottom-right corner of each modo viewport, a display shows the scale of the
small grid boxes. By default, the three orthographic views are linked together, but the
perspective view is independent. Because modo uses physical scale for many aspects of
lighting and texturing, it is important to check your scale as you begin to create models
in 3D space. I have seen many students (and, regrettably, myself) create large sections of
scenes only to realize that the pencil onscreen is as large as an oak tree—or bigger! In the
3D view, you will also see a light-colored grid that changes position and orientation based
on your perspective. This is the Work Plane, and it is a huge help when you begin modeling objects.
Figure 1.6 is a breakdown of the modo user interface (UI) with labels for the features
that are pertinent to this section.
Maneuvering in 3D Space Figure 1.6
The modo user
interface
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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. In a 2D application, the view controls are simple and are limited to panning, zooming, and rotating
the canvas. Interestingly, the addition of just one more navigational feature significantly
complicates the way that we interact with the environment.
Panning and zooming are relative to the perspective of the user, so they do not change
much. There are two ways to pan in 3D space: by clicking and dragging on the pan icon
in the upper-right corner of the view or by holding Alt (Windows) or Option (Mac) while
clicking and dragging.
Zooming can be achieved via one of three methods. As with the pan tools, there is a
zoom widget in the upper-right corner (this one zooms directly toward the center of the
view). Holding Alt+Ctrl (Windows) or Option+Control (Mac) while clicking and dragging zooms based on the position of the cursor. By using this method with the right
mouse button, a zoom area can be selected. This creates a box, and the area inside will
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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. Rotation works based on the combination
of two axes. Consider the way we rotate in two dimensions. With the x and y axes covering the screen horizontally and vertically, we can rotate along the perpendicular axis (in
this case, z). Because only two axes are present, we can rotate in only one dimension. The
addition of the third axis adds two more possible rotation options, as we now have three
planes to consider (xy, xz, and yz). As if this did not complicate things enough, there is
one more point to consider: the center of rotation. In a 2D layout, we rotate relative to the
center of the document. If we were to rotate only in relation to the origin (center of space),
we would be very limited in our access to the work area.
To move freely in a 3D workspace, we need to rotate our viewport dynamically. So
there are three types of rotation to deal with:
• Around the view focal point
• On a virtual tripod
• Rolling around the axis perpendicular to the perspective
Figure 1.7
Flat front view
of a model
Figure 1.7 shows a model from the front. Figure 1.8 shows that same object with the
view rotated to show the depth of the model.
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. This rotation technique keeps a set
distance from the center of view and always faces that point in space until another focus
is selected.
To rotate the view from a tripod, press Alt/Option and the right mouse button. The
tripod rotation works exactly like a real tripod: the orientation of the view is changed, but
the position of the view remains constant. This can be quite useful when working on large
scenes or architectural interiors. One thing to remember is that this option is specific to
views from cameras and lights, so the basic perspective view is not able to use tripodbased rotation.
Q u i c k T u r n ta b l e
Using the right mouse button to rotate in the perspective view enables the view to rotate on
its own. As soon as you release the button, the view continues to spin, with the speed based
on the mouse speed when the button was released. Moving slowly allows for slow and subtle rotation, while a quick flick of the mouse sends the view spinning rapidly. There is a falloff
of speed, and then the view comes to rest. This can also be done with the question mark (?)
key, which gives a single revolution around the scene.
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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. The A key is used to center on all visible items in the scene.
You can use the rotation tool to spin around your entire scene, and press Shift+A to focus
on a selection. By selecting the area you are interested in or working on, you can center
your perspective and rotate around the area in question. Subsequent chapters cover selections in more depth, but you can get started selecting by simply clicking and dragging
across some surfaces (polygons, edges, or points) in your scene. After you select something, pressing Shift+A will center your view on that selection.
Practice: Navigating in Space
Open the file Navigation_Practice.lxo from the included DVD. Spend a few minutes
moving around the scene. The more you navigate the space, the more comfortable it will
become. Start by moving around the objects generally, and then choose various sections of
the objects and manipulate the perspective until you get a good view of them. See if you
can get a side view showing all three objects aligned in the view. Remember to utilize all
of your newly learned navigation tools. Rotate, pan, and zoom your view. Use the A key
and Shift+A centering tools to center your view on an area of interest.
The practice file starts out with the viewport containing all three objects from an
angle, as seen in Figure 1.9. Try to duplicate the view shown in Figure 1.10. A few minutes
practicing with a simple scene such as this will reduce frustration when you have a more
complex scene and are still familiarizing yourself with the controls.
Moving Objects in 3D Space
Now that we have discussed moving around, you can begin to look at moving the objects
that you create. There are three methods for basic object manipulation: move, scale, and
rotate. Each of these tools (known as transform tools) can be activated by clicking the corresponding button on the left side, toward the top of the user interface, or by using their
hot keys. Each transform tool has some quirks or additional features that will speed your
workflow if you take advantage of them.
After a transform tool is activated, a property tab appears in the bottom-left corner.
The fields in this tab enable you to enter numeric values for each of the transform functions as well as control of some additional options for each tool. These values can be
entered by clicking in the fields and entering a value, by clicking on the arrows to increase
or decrease the values by small increments, or by clicking and dragging the arrows.
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.
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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. Clicking and dragging anywhere
but on the tool handles in the perspective view causes the handles to snap to the click
point, and dragging moves the object on the Work Plane. Clicking and dragging on the
circles moves the object perpendicular to the axis of the same color (red, green, or blue
for x, y, and z, respectively). While in the orthographic views, clicking and dragging on
the handles produces the same behavior as in the perspective view, and clicking off the
handles moves the object along the plane in view. The hot key for the Move tool is W.
Centering the Tool Handles
The default behavior of the tool handles to align to a click point is controlled by the Action
Center, which is set to Automatic when modo starts up. I cover Action Centers in depth in
future chapters, but for now, if the behavior is difficult to use, you can click Action Center
above the viewports and select Selection Center Auto Axis. This ensures that the tool handles remain in the center of the object and still align to the x, y, and z axes.
Next, let’s consider the Rotate tool. The handles for this tool are circles. Each circle
is colored like the circles on the Move tool. Clicking and dragging on these rotates the
object perpendicular to the axis of the corresponding color. Again, the active handle
turns yellow. Clicking off the handles snaps the tool to the click point, and dragging freerotates the object in all directions at once. This type of rotation is very difficult to control
and is not recommended. The gray circle that encompasses the rest of the handles rotates
the view and rotates the object perpendicular to the current view. In the orthographic
viewports, the gray circle is no different from the colored handles, but in the perspective
views, this will rotate variably based on the angle of view. This is a pretty special use, but
when it is needed, it can come in quite handy! Because rotation by its very nature takes
place around an axis, there is no way to rotate in a single direction, and so there are no
separate axes at one time (as with the Move tool). The hot key for the Rotate tool is E.
Pressing and holding the Ctrl / Control key prior to clicking a rotation handle causes the
angle of rotation to snap to 15-degree increments. This is useful when precise rotation is
required.
The Scale tool changes the size of the selected object or objects. The handles for the
Scale tool are similar to those of the Move tool. The Scale tool is visually differentiated
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. Unlike the Move tool, the Scale tool has another behavior
controlled by the cyan-colored circle at its center. This circle scales the object uniformly
in all directions. The hot key for the Scale tool is R.
The Transform tool is a combination of all three of the other transform tools (Move,
Scale, and Rotate). The question you may ask is, “Why on earth would I use individual
tools when the Transform tool does it all?” The answer is that it really doesn’t do it all.
Although the tool does provide the basic function of the Move, Rotate, and Scale tools,
it lacks several key options. The move portion of the Transform tool does not have planar handles. The scale portion lacks both planar handles and the uniform scale option.
Because the tool has to act on one axis at a time, it is often more productive to switch
tools and be able to scale or move in multiple (or all) directions at once. The Transform
tool comes in most handy when making quick adjustments to both movement and rotation. Mostly, this comes down to a matter of personal preference. Try the tools and see
which ones make the most sense to you and allow you to work the most efficiently. The
hot key for the Transform tool is Y.
Tools in modo are “sticky” and will remain active until the tool is dropped. A tool can
be dropped by pressing the spacebar, the Q key, or the Esc key. On subsequent presses,
the spacebar will switch modes between vertex, edge, and polygon. The Esc key will (with
additional strokes) clear out the tool pipe. I cover these functions in the next few chapters,
but because the Q key is bound only to dropping a tool, it is often the first choice for this
function.
Transform tools applied in vertex, edge, or polygon mode will alter the position of
geometry and cannot be reset with the exception of centering the selection by using the
Center Selected tool (under the transform tools on the left side of the screen). Objects can
be centered on any axis or combination of axes. When transforming objects in Item mode,
the changes are logged under the properties for the mesh layer. The Properties tab at the
bottom-right corner of the screen contains numeric fields for position, scale, and rotation.
After a change has been made, it can be adjusted or reset in the numeric fields on this tab.
Practice: Moving Objects
Open the file Transform_Practice.lxo from the included DVD. The file contains six cubes
in individual layers. When in individual layers, each object can be moved separately when
in Item mode.
1. Enter Item mode by clicking the Items button above the viewports (next to Vertices,
Edges, and Polygons).
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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.
Final position and
orientation of the
six cubes
Review
This chapter has covered an intro to 3D space as well as the basics of moving around our
viewports and objects in three dimensions. You have looked at some of the basic sections
of the user interface (UI) and learned some important hot keys. With the large number of
tabs, menus, and buttons in the interface, learning hot keys can be important to a quick
and efficient workflow. Here are the hot keys, to recap:
• Alt+Shift+click / Option+Shift+click = pan view
• Alt+Ctrl+click / Option+Control+click = zoom view
• Alt+click / Option+click = rotate view
• A = center view on all visible items
• Shift+A = center view on selection
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. These short videos show tools and procedures in action to help accelerate
the learning process.
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