Object Types

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There are a variety of objects that can be used when modeling in Shade. The proper type of object to use depends on the form you wish to model, and the result you are trying to achieve. Parts and Joints work a bit differently than other objects, and are explained later in this chapter. The Create tool, located in the Toolbox, is used to create objects. You can also access the Create tool submenu from the Tools menu, or from the contextual menu in the Figure window. The Create submenu can also be accessed in the Shortcut window. In this chapter, the types of Shapes in Shade will be used as examples in our descriptions. Later, we will create some simple shapes using the Toolbox.


Contents

Object Types

This tool is used to create shapes. By selecting the shape or light you want to create, you can create object shapes in the Figure window.

The Create Tool

Create Submenu in the Tools Menu

Create Submenu in the Contextual Menu

In the Windows version, the contextual menu appears when you press the right-button of the mouse in the Figure windows. For the Mac OS X version, the contextual menu appears when you press the mouse button in the Figure window while holding down the control key.

Line Objects

Line objects are the most basic of all the solid shapes manipulated in Shade. Line objects also become the source objects used to make the curved surfaces, extruded objects, and revolved objects to be described later. All three items from the top of the Create tool list, that is, Closed Line, Open Line, and Rectangle, are used to create line objects. The line objects in Shade are called Bezier Curves, and provide an intuitive way to manipulate objects consisting of both straight and curved lines. Closed lines that satisfy certain conditions can be converted to curved surfaces. You can also convert a group of closed lines, created from 3 or 4 points that do not have handles, to a polygon mesh.

Closed Line Objects

A closed line object created using the Closed Line tool is rendered as a plane surface. It is not just an outline, but a flat, filled-in shape, like a thin board. However, it is a board with zero thickness. Because the closed line is actually a plane object, all points making up the closed line are in the same plane. In other words, a shape like a bent or curved board cannot be created using closed lines (you have to use a curved surface). A closed line can be converted to an open line by clicking the Closed Line checkbox in the Object Info window, which is displayed by selecting the Object Info button in the Aggregate window.


Open Line Objects

An open line object created with the Open Line tool will not be visible in the rendered image. This is literally a line, meaning it has zero thickness, and is used as material for various modeling operations. An open line object can be converted to a closed line object. When this is done, the start and end points of the open line are automatically connected.


Rectangles

Shapes created with the Rectangle tool become closed line objects that have four control points. Manipulation of the created rectangle is the same as that of any closed line object. If a closed line created with the Rectangle tool is converted to an open line, it becomes a line object shaped like a sideways “U” character.

Disks

A Disk created with the Disk tool in the Create tool is a circular shape with a thickness of zero. In the Object Info window settings shown by selecting the Object Info button in the Aggregate window, you can set numeric values for its center coordinates and radii. If you set different values for the X and Y radii, you get an ellipse. Disks can also be converted to a sector or circular arc by changing the angle settings in the “From:” and “To:” fields. In the Figure window, a disk is displayed as a polygon with 16 sides, but it can be divided more coarsely or finely by changing the Surface Subdivision setting when it is rendered.

You can convert a disk to a closed line object, but then it loses its set values. Disks can also be used as the sources of extruded objects or revolved objects, to be discussed later. In this case, the disk continues to be a solid shape, keeping its set disk values.

Spheres

A sphere created with the Sphere tool in the Create tool is a spherical shape. In the Sphere window settings shown by selecting the Object Info button in the Aggregate window, you can set the numeric values of the center coordinates and the radii.

You can convert a sphere to a curved surface, but then it loses its set values.


Extruded Objects


Extruded objects are solid shapes created from a line object or disk, using the Extrude tool in the Toolbox’s solid tool. The original line object or disk is extruded (pulled out) linearly, keeping its settings. You can specify any direction in which to extrude, or you can set numeric values for that direction. If you create an extruded object from a closed line object, all points of the original closed line must be in the same plane.


The Clear command in the solid tool will restore the extruded object to its original line object or disk.

An extruded line object can be edited using Enter Modify Mode in the Modify tool. In this case, the original line object used as the source of the extruded object is edited, and then is automatically restored to the extruded object once the editing is finished.

If you convert an extruded object, it is dismantled into three parts: two line objects as the top and bottom planes, and a curved surface as a side plane. Similarly, if an extruded disk is converted, its top plane and bottom plane become closed line objects. In this case, the several values that specify the extruded object are lost.


Revolved Objects


Revolved objects are solid shapes based on line objects or disks. They are created using the Revolve tool in the Toolbox’s solid tool. The revolved object keeps the settings for the original line object or disk. In the Figure window, the revolved object is shown as a polygon with 16 sides, but it can be divided more coarsely or finely by changing the Surface Subdivision setting when it is rendered. The revolve axis is specified by dragging a line when you create the revolved object. The revolve angle can be changed by entering numeric values for the start and end angles (use the Object Info command).


The Clear command in the solid tool will restore the revolved object to its original line object or disk.


A revolved line object can be edited using Modify Control Points in the Modify tool. In this case, the original line object used as the source of the revolved object is edited, and then is automatically restored to the revolved object once the editing is finished. You can convert a revolved object into a curved surface. In this case, the several values that specify the revolved object are lost.


Curved Surfaces

Since a curved surface can be manipulated most freely of all the shapes in Shade, it is suitable for creating complicated shapes or delicate curved surfaces.

Because a curved surface consists of line objects sectioned vertically and horizontally, it is manipulated by editing those individual line objects. More detailed information on creating and manipulating curved surfaces is provided in a later chapter.

Curved surfaces can be converted to a polygon mesh by specifying the numbers of surface subdivisions.

Polygon Meshes


A polygon mesh is expressed as a cluster of surfaces, and can be modeled with much flexibility, similar to a curved surface.

You can create a polygon mesh not only by converting different types of shapes, but by importing shapes from other programs. When you export shapes to be used in other programs, the polygon mesh offers the advantage of being highly compatible. In Shade, if the number of vertices of each plane in a polygon mesh is four or less, the polygon mesh is rendered as planes. If a plane has five or more vertices, it will have holes when rendered.

If you convert a polygon mesh, it becomes a cluster of closed lines, with each plane becoming an independent shape.

MetaMeshes


A MetaMesh is a type of polygon mesh that is automatically generated from Meta-elements. There are four different types of Meta-elements: MetaBalls, MetaCubes, MetaCylinders, and MetaPolygons. You can create a MetaBall, MetaCube, or MetaCylinder using the Create tool in the Toolbox. A MetaPolygon is generated by converting an existing polygon mesh with Convert to MetaPolygon in the Modify tool.

Meta-elements have the property of automatically fusing together. Simply bringing them near to each other allows you to easily create a smoothly-fused MetaMesh.

A MetaMesh, when it is created, is automatically associated with the Native MetaRenderer. Accordingly, if you render it with the Ray Tracing method, you can get a smooth rendered image in which the object is not converted into a polygon mesh.

Creating Rectangles

  1. Select Rectangle from the Create tool in the Toolbox.
    The Create tool becomes active.
  2. Drag the mouse from A to B within the Top view.


A rectangle is created based on the diagonal line connecting A and B, and a “Closed Line” appears in the Browser.


Setting the Position of the 3D Cursor

In the Front view, let’s create a second rectangle that crosses near the center of the first rectangle.

  1. As you move the mouse pointer back and forth In the Front view, watch the motion of the 3D cursor in the Top view.
    Move the mouse pointer back and forth In the Front view You can see that the 3D cursor in the Top view moves parallel to the X axis. To create a shape that crosses near the center of the rectangle, you need to set the Z-axis (depth) coordinate value of the 3D cursor.
  2. Move the mouse pointer to Point A in the Top view of the Figure window, then click.
    The depth coordinate value of the 3D cursor is changed. If another shape exists at a position you click in the Figure window, clicking within the Figure window while holding down Ctrl key (Win) / option key (Mac) enables you to set the position of the 3D cursor without affecting any active shape.
  3. Again, move the mouse pointer back and forth in the Front view and verify that the Z-axis coordinate value has been changed.
  4. Select Rectangle from the Create tool in the Toolbox, then drag the mouse from B to C in the
Front view.
The new shape is created.

Using the Ruler to Set the 3D Cursor Position

Another way to change the 3D cursor’s position is to use a ruler. You can use a ruler anytime to set the position of the 3D cursor, no matter what tool is currently active. This method does not affect any shape, just as in the case of the operation in which you click within the Figure window while holding down the Ctrl key (Win) / option key (Mac).

In the Side view, let’s create a shape that crosses near the center of the two existing rectangles.

  1. Select Rectangle from the Create tool in the Toolbox. (Figure 8)
  2. Move the mouse pointer around within the Side view, without clicking the mouse button.
    You can see the current X-axis (width) coordinate value of the 3D cursor by observing the Front and Top views. To create a new shape near the center, you need to change the X-axis coordinate value.
  3. Move the mouse pointer within the Front view, then click Point A on the X-axis ruler.
    The coordinate value for the 3D cursor is changed.
  4. Move the mouse cursor into the Side view and drag from B to C.
    A new shape is created.

Knowing how to set the coordinates of the 3D cursor is very important, not only when creating rectangles, but when creating or editing any shape.


Creating a Disk

Now let’s create a disk above our rectangles and review how to set the position of the 3D cursor.

  1. Move the mouse cursor into the Front view of the Figure window, then click Point A on the Y-axis ruler.
    The height of the 3D cursor is set.
  2. Select Disk from the Create tool in the Toolbox. (Figure 13)
  3. Drag the mouse from B to C within the Top view.
    A disk is created above the rectangles. “Disk” also appears in the Browser.

Creating a Sphere

In the Front view, let’s create a sphere above the disk.

  1. Scroll the Figure window to easily create a sphere above the disk. Move the mouse pointer within the
Front view to check the Z-axis (depth) cursor position
If you look at the Top view and see that the 3D cursor is not at the center of the disk, click within the Figure

window or on the Z-axis ruler to set the Z-axis cursor position.

  1. Select Sphere from the Create tool in the Toolbox.
  2. Drag the mouse from A to B to create a sphere.

This creates a sphere with a radius equal to the distanceyou drag, and “Sphere” appears in the Browser.

Converting Objects

The Convert tool in the Toolbox allows you to convert certain objects to a different object type. When you click the Convert tool a submenu pops up displaying a list of object types to which the currently selected object can be converted. The available choices change according to the type of object that is currently selected.

Converting a Closed Line

A closed line can be converted to a curved surface or a polygon mesh.

Converting to a Curved Surface

Closed lines with exactly four control points can be converted to a curved surface with no modifications. To convert a closed line with more than four control points (the total number of control points must be even), first select the curved surface in the Browser and enter Modify mode. Select the first two points and the last two points in the direction that you want to create the curved surface. Now the “Convert to Curved Surface” option is available from the Convert tool. The “Hole” checkbox in the Object Info window is ignored when converting to a curved surface. The conversion is done automatically; there are no settings to assign.

Converting to a Polygon Mesh

Closed lines with at least three control points can be converted to a polygon mesh. Closed lines with only two control points can be converted only if one of the two control points has a tangent handle. <true?> Before the closed line is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting an Open Line

An open line cannot be converted to another object type.

Converting a Rectangle

A rectangle, as a closed line, can be converted to a curved surface or a polygon mesh.

Converting to a Curved Surface

The conversion is done automatically; there are no settings to assign.

Converting to a Polygon Mesh

Before the rectangle is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting a Disk

A disk can be converted to any of the following: a closed line, an open line, a curved surface, or a polygon mesh.

Converting to a Line Object

If the selected object is a disk (a closed circle) it will be converted to a closed line. If the selected object is an arc (an incomplete disk) it will be converted to an open line. The conversion is done automatically; there are no settings to assign.

Converting to a Curved Surface

A disk will be converted to a curved surface composed of four arc segments.

Converting to a Polygon Mesh

Before the disk is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting a Sphere

A sphere can be converted to a curved surface or a polygon mesh.

Converting to a Curved Surface

A sphere will be converted to a curved surface composed of three latitudinal closed lines and four longitudinal open lines. Of the three latitudinal closed lines, one encircles the equator of the sphere and the other two are reduced to single points at each pole. The conversion is done automatically; there are no settings to assign.

Converting to a Polygon Mesh

Before the sphere is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting an Extruded Object

An extruded object can be converted to a curved surface or a polygon mesh.

Converting to a Curved Surface

When an extruded closed line or a disk is converted to a curved surface, the surface created by the extrusion is converted as a curved surface and the faces that form the start and end points of the extrusion (i.e. the “lids” of the extrusion) are converted as closed lines. If the number of control points composing the object before extrusion is “u”, then the surface created by the extrusion will be converted to a curved surface with “u x 2” control points. Put simply, an extruded disk will be converted to a curved surface with a 4 x 2 lattice structure. When an extruded closed line is converted to a curved surface, the “Hole” checkbox in the Object Info window is ignored.

Converting to a Polygon Mesh

Before the extruded object is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting a Revolved Object

A revolved object can be converted to a curved surface or a polygon mesh.

Converting to a Curved Surface

The surface that is created during the Revolve operation is converted as a curved surface. If the revolved angle is not a full 360 degrees, the solid will have a start and end surface; these surfaces will be converted as closed lines. If the number of control points composing the object before it is revolved is “u”, then the surface created by the revolution will be converted to a curved surface with “u x 4” control points. The conversion is done automatically; there are no settings to make.

Converting to a Polygon Mesh

Before the revolved object is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision.

Converting a Curved Surface

A curved surface can be converted to a polygon mesh or pseudo polygon mesh.

Converting to a Polygon Mesh

Before the curved surface is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision. The Division (lateral) textbox allows you to specify the number of subdivisions for the line objects that are currently displayed. The Division (longitudinal) textbox allows you to specify the number of subdivisions for the line objects perpendicular to those currently displayed.

Converting to a Pseudo Polygon Mesh

Before the curved surface is converted to a pseudo polygon mesh, the Convert to Pseudo Polygon Mesh dialog box appears, allowing you to choose the level of subdivision. The settings here are the same as when converting a curved surface to a polygon mesh, as explained above. Note: For more on pseudo polygon meshes, see “Pseudo Polygon Meshes” on page 17.

Converting a Polygon Mesh

A polygon mesh can be converted to a group of line objects.

Converting to Line Objects

Each face of the polygon mesh is converted to a closed line, and all of these closed lines are grouped together under one part. The group of closed lines can then be re-converted to a polygon mesh as needed. Multiple polygon meshes can be converted to a single polygon mesh by grouping each of them under a single part, and then choosing “Convert to Polygon Mesh” with that part selected.

Converting a Pseudo Polygon Mesh

A pseudo polygon mesh can be converted to a polygon mesh or re-converted to a pseudo polygon mesh with a different level of subdivision.

Converting to a Polygon Mesh

Before the pseudo polygon mesh is converted to a polygon mesh, the Convert to Polygon Mesh dialog box appears, allowing you to choose the level of subdivision. The settings here are the same as when converting a curved surface to a polygon mesh, as explained above.

Re-converting to a Pseudo Polygon Mesh

The Convert to Pseudo Polygon Mesh dialog box will appear, allowing you to specify a different level of subdivision. The settings here are the same as when converting a curved surface to a polygon mesh, as explained above.

Front and Back of Surfaces

You can specify which side of a surface is the front and which is the back, and the way in which surfaces are displayed in Shade when you are exporting a surface to another 3DCG system. You do not have to worry about the sides of a surface for any other case.

Sides of a Surface

Some 3DCG systems display only one side -- that is, the front side -- of a surface due to processing speed and memory consumption. The front and back sides of a surface are determined by the order of vertices as viewed from the current position -- that is, whether vertices are ordered clockwise or counterclockwise.

The direction of a surface can always be confirmed by quick rendering. It can also be reversed at any time. The front and back sides of a surface are determined as follows. In all cases, objects are seen from the positive direction of the plane on which the object has been created. For objects created with the Closed Line tool or polygon meshes, the upper side is the front side when control points are ordered clockwise. All other open line objects will have the upper side as the front, and closed line objects will have the outside as the front. For example, when you create a ceiling for a room in the Top view, the back of the ceiling is visible when you look up at the ceiling. For extruded objects, when the extrusion is directed toward the positive direction, the outside is the front side; likewise, for revolved objects, when the axis of revolution is located at the positive side of the object, the outside is the front side. For example, when you are creating a room by extruding a rectangle, the back side of the room is visible from inside the room, provided that the extrusion is directed toward the positive direction.

Retaining the Sides of a Surface

The sides of a surface are retained after transformation. The Invert Face checkbox may be switched on or off as required during transformation. When you transform a closed line object with mixed front and back sides into a polygon mesh, surfaces that share control points are aligned to either direction. Isolated surfaces retain the pre-transformation status. Sides of a surface are retained in the following cases as well: Using the Reverse and Switch in the Modify tool; Using the Scale in the Move tool to zoom in/out toward the negative direction. In either case, the front and back side of a surface can be exchanged at any time; you do not have to be concerned about it during the modeling process.

Reversing the Direction of a Surface – Invert Face Checkbox

You can reverse the direction of a surface by switching on/off the Invert Face checkbox in the Browser window. Because the sides of a surface are retained when using the Reverse and Switch in the Modify tool or the Scale in the Move tool to zoom in/out toward the negative direction, the Invert Face checkbox is switched automatically.

Inheriting the Reversal of Surfaces

The Invert Face setting affects all parts at lower hierarchical levels.

Displaying Surfaces – Single Sided and Double Sided

The back side of the surface will not be displayed if you choose Single-sided in the Rendering menu during quick rendering.

The back side of the surface can be hidden by selecting Flat shading from the shading pull-down menu within the Basics settings of the Rendering option and similarly turning on the other Single Face checkboxes in the Rendering option when rendering with the Scan Line technique. |

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