Construction of 3D Primitive Geometric Objects

Keep in mind the data entry and graphic cursor construction techniques described in the Geometry Overview. The same rules for creating primitive geometric objects in 2D apply for 3D. The mouse cursor is used for locating control points in the Model View, and the input fields in the Geometry tab override the cursor location.

For example, if you wish to create a point, you may supply the Z-coordinate in the input area by enabling the Z: toggle switch and entering a specific Z coordinate. Now when you move the mouse cursor to the screen and click the left mouse button, a point will be created using the X and Y coordinates from the screen, and the specified Z coordinate from the input area.

As in 2D input, the objects may be created parametrically or in a repeating fashion. Note when dimensions are explicitly entered in the input area, for example the radius of a sphere, a sphere with the given radius will be created at the location specified when you click the mouse button. If you happen to specify the X, Y, or Z coordinate of the location of the center of the sphere in the input area, the specified coordinate(s) will be used to define its location.

Before creating 3D primitive geometric objects, you must first select the 3D reference system in the Reference/ Theory Toolbar and then select Class > Geometry or the Geometry tab in the Input dialog. As described in the Geometry Overview, geometry construction also relies heavily on the Class > Action > Object > Method (C/A/O/M) command paradigm. In geometry construction the most important Action is of course Create. To access geometric construction of 3D primitive geometric objects (i.e. solids and surfaces), first enable Surface in the Surface/Curve Selector:

Note: by default solids are a dark blue color (Figure 1b), whereas surfaces are a bright blue color (Figure 1c).

Solids and surfaces are used in 3D in much the same way that curves are used in 2D, as a basis for describing the finite element mesh in an associative and sometimes parametric way. Solids and surfaces may be created as primitive objects or as the result of boolean, blend, clipping or other modeling operations.

• Sheet Body Operations
• 3D Solid Body Operations

Once an object has been selected a method must be chosen. While not all methods may be appropriate for every object, each method works in a consistent way for every corresponding object. For a complete list of creation methods, consult Primitive Geometry Creation Methods.

Surface/Solid Objects Overview

In StressCheck, there are five types of three dimensional objects: a solid body, a sheet body, a wireframe body, a surface and a curve. Solid, sheet and wire bodies are considered to be topological objects, while surfaces and curves are considered to be geometric objects. Both solid bodies and sheet bodies may be composed of point, curve and surface geometric objects. Wireframe bodies are composed of curve and point geometric objects.

Solid Bodies

Solid bodies are a representation of a three dimensional bounded volume. A solid body may be a simple primitive such as a box, sphere, cylinder, cone or torus. It may also be a complex object formed by a boolean, blend or clipping operation involving two or more solid bodies, and represented by a collection of faces (trimmed surfaces), edges (trimmed curves) and vertices (points). By definition a “parent” solid body is composed of “child” point, curve and surface geometric objects. These child objects may not be modified directly by the user; rather they are controlled by the definition of their parent solid. On the other hand, these child points, curves and surfaces may be referenced by other objects in explicit associative relationships, or for the purpose of defining boundary conditions in the finite element model.

Solid bodies do not have parametric limits in the same way that sheet bodies do. Solids are composed of child surfaces, which are trimmed by the intersection curves that define the connection between neighboring surfaces in the solid object. However, the surfaces which compose a solid have the same 2-parameter (U,V or P1, P2 in StressCheck) reference system as sheet bodies have for purposes of associating objects or defining boundary conditions. To create a Solid body, depress the Solid toggle.

Sheet (Surface) Bodies

Sheet bodies are three dimensional surface objects that do not represent a volume and do not have thickness. A surface object may be a simple primitive such as a plane, sphere, cylinder, cone, torus, surface of revolution, tabulated cylinder, extruded body, or spline surface. In general, a sheet body is a bounded rectangular patch defined in a 2-parameter system. You may control the extent of the rectangular patch by supplying limits in the U,V (P1, P2 in StressCheck) parameter system. For example, you may define a cylindrical sheet body with Radius=1, Height=2, and parameter limits P1min,P1max = (0,90) and P2min,P2max = (0.25,0.75). Similarly, a point on the surface of a sphere may be identified by a pair of surface coordinates representing the longitude angle (0 degrees ≤ P1 ≤ 360 degrees) and latitude angle (-90 degrees ≤ P2 ≤ 90 degrees).

In general, we refer to sheet bodies as surface objects, and solid bodies as solid objects. As mentioned above, both may be composed of point, curve and surface geometry; however, the user does not directly control the definition of geometric objects. The user is only in control of topological objects. To create a Surface body, do not depress the Solid toggle (the toggle should be labeled “Surface”).

Parametric Surface/Solid Bodies

Most 3D surface and solid objects in StressCheck are defined by a location and one or more basic dimensions of the object. For example, the sphere is described by the X, Y, Z location of its center, and a radius. Each of these may be defined parametrically. To create a sphere, you may enter the X, Y, Z coordinates, the radius, and, if defining a surface, the P1 (P1-Min: 0, P1-Max: 360) and P2 (P2-Min: -90, P2-Max: 90) values into the input fields of the Input dialog. Note: If creating a solid, depress the Solid toggle so it is labeled “Solid”. If creating a surface, do not depress the Solid button (it should be labeled “Surface”). Click on the Accept button or move the mouse cursor to the Model View and click the left mouse button. Remember that it is necessary to enable each input field in order to enter location and dimension information.

Editing Surface/Solid Objects

Once a 3D surface or solid primitive has been created, it may be edited graphically. In the case of a cylinder surface or solid, simply choose Action: Edit, Object: Cylinder, and use the graphic cursor to select the cylinder you wish to edit from the Model View. The dimension information will appear in the input area (only in fields which are disabled for manual data entry). You may now enter new dimension information and click the Replace button to change the object definition. Only those dimensions associated with enabled input fields will be changed for the selected object.

For example, if the cylinder is originally defined with Radius=10.0 and Height=30.0, and you enable only the Radius: input field, enter any nonzero value and click Replace, only the radius of the cylinder will be changed to the value specified. Note: You may also use a generic object type such as Any Body or Any Boundary to edit a solid or surface.

Surface/Solid Orientations

Another common editing operation performed on 3D surfaces is to change the orientation of the surface. By default all system based surfaces and solids, such as planes, spheres, cylinders, cones, and tori, are created such that the xy-plane of the local system associated with the surface is parallel to the XY-plane of the global coordinate system when the XYZ rotation angles are zero. This condition is illustrated in Figure 3.

When a system based surface is graphically constructed, the XZ plane of the local system is created in the plane of the screen. To change the orientation of an object, you must edit the local system associated with the object. This can be accomplished as follows:

• Choose Action: Edit
• Choose Object: System
• Make sure that all input fields are disabled for manual input
• Use the mouse cursor to select the local system of the surface/solid you wish to modify
• Change the local system rotation values (rot-X, rot-Y, rot-Z)
• Click the Replace button to update the definition of the local system and associated 3D object.

Surface/Solid Bounding Curves

Sheet and solid bodies are composed of geometric point, curve and surface primitives. In some cases, a solid or sheet body may have been constructed from preexisting curve or surface primitives. For example, a ruled surface or a spline surface may be constructed by joining geometric curves with a sheet body composed of new point, curve and surface primitives. In this case, the curves represent the bounding curves that define the extent of the sheet body.

Visually, the original construction curves and the new bounding curves may be easily confused. It is important to distinguish them when constructing a finite element mesh by hand. In most cases, manually created (hand-meshed) nodes should be attached to bounding curves, and not to the underlying construction curves, in order for the elements to be properly associated with the parent sheet body surfaces.

Before defining any nodes that are to be attached to bounding curves, it is a good practice to first hide the underlying construction curves, so that they will not be selected by mistake when attaching nodes. One technique for doing this is to set the C/A/O/M to Select > Any Curve > Selection, marquee select all the curves associated with the sheet body, click on the Index subtab, and then de-select the “SurfCurve” objects by left clicking on the associated items in the Index list; only the construction curves should have the status “Selected”. Then, hide the construction curves by selecting “Hide Objects” > “Curves” on the “Edit” toolbar. When you pick curves during subsequent node creation operations, the nodes will only be attached to the desired bounding curves.

Surface Patches

It is sometimes desirable to limit the portion of a surface which is displayed to some range of the P1, P2 parameters. The default parameters for the sphere for example, are 0 degrees ≤ P1 ≤ 360 degrees and -90 degrees ≤ P2 ≤ 90 degrees. This may be accomplished by enabling the range parameters and entering the desired ranges when the surface is created, or editing them afterwards.

For example, to create a sphere surface patch, the range for the first parameter could be set to 250 ≤ P1 ≤ 325, and the range for the second parameter 0 ≤ P2 ≤ 45. Note: the parameter range of a solid primitive cannot be modified in this manner. As a result, solid primitives do not have a P1 or P2 parameter range option.

Zero-Dimensional Objects

Coordinate System Object (i.e. System)

To create a System object, set the C/A/O/M to Create > System, and choose the desired method (see below for the supported methods).

Overview

Local coordinate systems are fundamental geometric objects in StressCheck. Local systems give you the ability to conveniently orient objects in 2D or 3D space. You may also attach a local system to another local system in order to build up a complex geometric assembly. For example, imagine a robot arm with a local system at each joint: shoulder, elbow, wrist, finger, and knuckle. If you rotate the system at the elbow of the arm, the objects defining the forearm, hand and fingers will rotate simultaneously.

The basic information required to define a local system is its coordinate location and its orientation. Some construction methods reduce the amount of information required by the user to define a system, since the X,Y, Z coordinate location can be computed from an associative relationship like an offset (e.g. 45 degree offset on a circle), intersection, projection, or other associative relationship. Defining an associative relationship always requires a graphic mouse selection to determine the base object(s). Figure 4 illustrates a simple local Cartesian coordinate system definition and its visual representation. Note that there is a graphic embellishment of each principal axis of the local system. Each axis is displayed in a different color (X=blue, Y=green, Z=red).

Local cylindrical (R, θ, Z) and spherical (R, θ, φ) coordinate systems are visually represented like Cartesian systems and are indicated by a C or S, respectively. The coordinate system conventions used in StressCheck are illustrated in Figure 5.

For cylindrical systems, the radius (R) is the distance from the z-axis to the point, the azimuth angle (θ) is measured counter-clockwise from the x-axis in the x-y plane, and the height (Z) is identical to its Cartesian counterpart. For spherical systems, the radial distance (R) is the distance from the origin to the point, the azimuth angle (θ) is measured counter-clockwise from the x-axis in the x-y plane, and the polar angle (φ) is measured from the z-axis to a line segment drawn between the origin and point.

Supported Methods

• 3-Pt Plane
• Delta
• Intersect-Multi
• Intersection
• Local
• Locate
• Mid-Offset
• Midpoint
• Offset
• Point
• Projection
• Sample

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Example: 3-Pt Plane Method

To create a Cartesian system passing through three points select Action: Create > Object: System > Method: 3-Pt. Plane, Data Type: Cartesian. The system is located at the position of the first pick point, the x-axis is in the direction of the line from point 1 to point 2, and the z-axis is normal to the plane defined by the 3 points.

Point Object

To create a Point object, set the C/A/O/M to Create > Point, and choose the desired method (see below for the supported methods).

Overview

The basic definition of a point is a geometric coordinate location X,Y, Z (R, Z in Axisymmetric analysis). Points will appear as a brown “+” symbol. Points may be created by several methods, and may be used as the basis for other associative objects such as lines, splines, circles, etc. Points are to be distinguished from nodes, which are element topological objects. Points cannot be used in the definition of an element, only nodes may be used in this way.

Supported Methods

• Delta
• Intersect-Multi
• Intersection
• Local
• Locate
• Mid-Offset
• Midpoint
• Offset
• Projection
• Sample

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Primitive Surface Objects

The following sections describe basic construction techniques for each of the 2D/3D surface (sheet body) objects currently supported in StressCheck. It is important to pay particular attention to the definition of the surface coordinate ranges since node definitions are often associated with surfaces using the surface coordinates.

Plane Object

To create a Plane surface object, set the C/A/O/M to Create > Plane, and choose the desired method (see below for the supported methods).

Overview

A plane is defined by the coordinates of its local origin, a width and a height. The surface coordinates are defined in the range -0.5 ≤ P1 ≤ 0.5, and -0.5 ≤ P2 ≤0.5. The surface coordinates may be understood to be a fraction of the actual dimension of the plane in each direction (Figure 6). When using the 3-Pt Plane method, the local origin is located at the first point picked.

Supported Methods

• 3-Pt Plane
• Delta
• Local
• Locate
• Offset
• Point
• Sample

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Circle Object

To create a Circle surface object, set the C/A/O/M to Create > Circle, and choose the desired method (see below for the supported methods).

Overview

The basic definition of a circle is a coordinate location of its center and a radius. By default, a circle is automatically created with a local system at its center so that it is easy to move the circle and to introduce an orientation in 2D or 3D space. Figure 7 illustrates the visual appearance of a circle object.

Supported Methods

• 3-Pt Circle: A circle may be defined by the 3-Pt Circle method in which the circle will pass through all three selected points.
• 3-Pt Circle(CRP): A circle may also be defined by the 3-Pt CRP (center, radius, point) method. In this case, the first point represents the center of the circle, the second point established the radius of the circle and the direction of the local x axis, and the third point establishes the plane in which the circle lies. The circle is a complete 360 degree circle.
• Delta
• Local
• Locate
• Offset
• Point
• Sample
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Ellipse Object

To create an Ellipse surface object, set the C/A/O/M to Create > Ellipse, and choose the desired method (see below for the supported methods).

Overview

The basic definition of an ellipse is a coordinate location of its center, a major axis radius (R1) and a minor axis radius (R2). By default, an ellipse is automatically created with a local system at its center so that it is easy to move the ellipse and to introduce an orientation in 2D or 3D space. Figure 8 illustrates the visual appearance of an ellipse object.

Supported Methods

• Delta
• Local
• Locate
• Offset
• Point
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Surface of Revolution Object

To create a Surface of Revolution object, set the C/A/O/M to Create > Surf. Rev. > Selection.

Overview

A surface of revolution is defined by an arbitrary 2D curve and a line which represents the axis of revolution. The surface coordinates are defined in the range 0 ≤ P1 ≤ 360, and 0 ≤ P2 ≤ 1. The surface coordinate in the direction of the basis curve (P2) is understood to be a fraction of the curve length.

To construct a surface of revolution in StressCheck requires that you first construct 2D curves as illustrated in Figure 9a. After constructing the 2D curves, select the curve to be rotated first, then the line which is to be used as the axis of revolution. By default, the surface will revolve about the axis the full 360 degree range (Figure 9b). You may supply the start angle (P1-Min) and end angle (P1-Max) in the input area if you wish to restrict the angle of revolution.

Note: For this operation composite curves are not admissible. Instead, you may create a surface of revolution from each segment which makes up the composite curve and combine those surfaces into one sheet body via Create > Body > Bool-Union.

Tabulated Cylinder Object

To create a Tabulated Cylinder object, set the C/A/O/M to Create > Tab. Cyl., and choose the desired method (see below for the supported methods).

Overview

A tabulated cylinder is defined by an arbitrary 2D curve and a point which does not lie on the curve, (or a line) representing the direction of extrusion from the curve at P1 = 0. The surface coordinates are defined in the range 0 ≤ P1 ≤ 1, and 0 ≤ P2 ≤ 1. The surface coordinates in each direction are understood to be a fraction of the defined surface dimensions.

To construct a tabulated cylinder StressCheck requires that you first construct a 2D curve and a point (or line), as illustrated in Figure 10a. Then, simply select the curve and the point (or line) with the mouse cursor (Figure 10b).

Supported Methods

• Point: Use method “Point” to create a Tabulated Cylinder using a reference point (Create > Tab. Cyl > Point).
• Selection: Use method “Selection” to create a Tabulated Cylinder using a reference line (Create > Tab. Cyl > Selection).

Ruled Surface Object

To create a Ruled Surface object, set the C/A/O/M to Create > Ruled Surf. > Selection.

Overview

A ruled surface is defined by connecting two arbitrary curves. The surface coordinates are defined in the range 0 ≤ P1 ≤ 1, and 0 ≤ P2 ≤ 1. The surface coordinates in each direction are understood to be a fraction of the defined surface dimensions.

To construct a ruled surface StressCheck requires that you first construct two curves as illustrated in Figure 11a, then simply select the two curves with the mouse cursor (Figure 11b). The two curves must be oriented so that the positive parameter direction is the same.

Note: If the ruled surface appears to be twisted, it is possible that one of the boundary curves has a reversed parameter direction with respect to the other curve. Use the Reverse method (Select > Any Curve > Reverse) to change the sampling direction of one of the curves.

Offset Surface Object

To create an Offset Surface object, set the C/A/O/M to Create > Offset Surf. > Selection.

Overview

An offset surface is defined as a replica of a 3D surface which has been offset from the original surface. Each point on the new offset surface is located at the specified distance from a corresponding point on the base surface, in the direction of the normal vector at each point. Note: the surface normal may be displayed at any location on the surface by using Check > Any Surface > Offset.

To construct an offset surface StressCheck requires that you first construct a 3D surface (as illustrated in Figure 12 as the outer surface), then supply the offset distance in the input area and select the surface with the mouse cursor. In this case, the outer surface normal results in the inner offset surface in Figure 12. Be sure that the offset surface is not self-intersecting, or an error message will appear. To locate points or nodes on the offset surface, use the same surface coordinate system as the originating surface.

Fillet Surface Object

To create a Fillet surface object, set the C/A/O/M to Create > Fillet > Selection.

Overview

A fillet surface represents the shape of the path traced between two surfaces by a rolling ball. The surface coordinates are defined in the range 0 ≤ P1 ≤ 1, and 0 ≤ P2 ≤ 1. The surface coordinates in each direction may be understood to be a fraction of the defined surface dimensions.

To construct a fillet surface in StressCheck, it is required that you first construct the two surfaces to be filleted as illustrated in Figure 13a, supply the fillet radius in the input area, and select the two surfaces with the mouse cursor (Figure 13b). The proximity of your cursor picks will determine on which side of each surface the fillet surface will appear.

Note: when creating hand-meshed elements attached to a fillet surface, it is important to place nodes exactly on the edge of the fillet surface (P1=0.0 and P1=1.0), or to attach them to the intersection curve which is constructed automatically to represent the point of tangency between the fillet surface and the parent surfaces. This will ensure that the associativity with the secondary surfaces will be recognized when one edge of the element lies along the edge of the fillet and the other edges lie on one of the parent surfaces.

Spline Surface Object

To create a Spline surface object, set the C/A/O/M to Create > Spline, and choose the desired method (see below for the supported methods).

Overview

A spline surface is a form of fitted surface constructed from a set of control points obtained from an underlying set of 2D curves oriented in 3D space (Figure 14a). The surface coordinates are defined in the range 0 ≤  P1 ≤ 1, and 0 ≤ P2 ≤ 1. To construct a spline surface in StressCheck requires that you first have a set of at least two 2D curves. These curves may be of any type, and may be defined as open or closed. In the example shown in Figure 14b the spline surface is associated with a spline curve, two circular arcs, and an elliptical arc.

To construct the spline surface, simply use the mouse cursor to select each curve in the order you wish to use them to represent the surface, and double click on the final curve to indicate that you are finished selecting curves.

StressCheck will automatically choose the polynomial order of the spline fitting. The surface remains associative, so that if you change the definition of any of the underlying curves, the surface will automatically be re-evaluated. If you make a mistake while selecting curves, use the Backspace key to de-select the last curve selected.

A spline surface must have at least two sampling curves. If the spline surface appears to be twisted, it is possible that one or more of the 2D boundary curves have a reversed parameter direction with respect to the other curves used. Use the Reverse method (Select > Any Curve > Reverse) to change the sampling direction of the erroneous curve.

Spline Surface Closure Conditions

Note that the input fields labeled P2-Bot and P2-Top provide additional control over the shape of the surface in the P2 parameter direction. To use this advanced feature, the inputs should only be assigned non-zero values if the surface will be closed in the P2 parameter direction. If a value of zero (0) is assigned, or if the toggle is turned off, the surface will appear open in the P2 parameter direction. If a value of one (1) is assigned, the surface will be closed like a cup at the corresponding edge of the surface (either where parameter P2 is minimum or where it is maximum).

The closure condition is obtained by averaging the sample points from the first profile (P2-Min) or last profile (P2-Max) and adding an additional profile to the surface definition consisting of a small circle at the computed average location. If a value of two (2) is assigned, the closure condition will be obtained by averaging the sample points from the first or last profile and replacing that profile with the new computed points. In other words, when P2-Bot/Top is assigned a value of one (1) the spline surface will be capped and rounded off at that end while still maintaining the overall shape. When P2-Bot/Top is assigned a value of two (2) the spline surface will taper down to a point in which that point is the computed average location of the end profile.

Supported Methods

• Selection: Use the “Selection” method (Create > Spline > Selection) to construct the spline surface by selecting wireframe curves. Simply use the mouse cursor to select each curve in the order you wish to use them to represent the surface, and double click on the final curve to indicate that you are finished selecting curves.
• Offset: Use the “Offset” method (Create > Spline > Offset) to construct a spline surface which is at a fixed distance from a reference surface. A series of sample points, the number of which is specified as an input value (Res:), is computed on the reference surface. The computed construction points are then used to construct the new spline surface. The resulting spline surface maintains an associative relationship with the reference surface. The offset value may be parametric.
• Mid-Offset: Use the “Mid-Offset” method to construct a spline surface which is positioned relative to two reference surfaces. A series of sample points, the number of which is specified as an input value (Res:), is computed based on sample points taken from the reference surfaces. Moving along each surface from the initial offset to the final offset in each u,v direction, a sample point is taken and new construction point is computed. If the offset value provided is 0.5, each point on the resulting spline surface will be equidistant from the reference surfaces. The resulting spline surface maintains an associative relationship with the reference surfaces. The offset value may be parametric. To construct the mid-offset surface, click once on each of two surfaces. If the resulting surface is twisted, it may be necessary to use the Select > Any Curve > Reverse technique to reverse one of the surfaces. Note: The Repeat feature may be used to construct several spline surfaces with one construction operation. The Offset method may be used to construct a spline associated with all selected surfaces by entering the appropriate input and clicking on the Accept button.

Formula Surface Object

To create a Formula surface object, set the C/A/O/M to Create > Formula, and choose the desired method (see below for the supported methods).

Overview

The formula surface object is a surface defined by formulas which determine the value of the X, Y, and Z coordinates of the surface with respect to two independent variables (X and Y). The independent variable ‘X’ is controlled by the parameter P1, in which the range of inputs into the formulae are controlled by P1-Min and P1-Max. The independent variable ‘Y’ is controlled by the parameter P2 in the same manner as P1. The formula object will be associated automatically with a local system in which the dependent variables (X,Y,Z) will be evaluated. This also makes it possible to easily orient the surface after it is created.

Figure 15a represents the formula expressions (xfmla, yfmla, zfmla) used to generate the formula object, and Figure 15b represents the formula input fields for C/A/O/M Create > Formula > Locate. Figure 15c illustrates the visual appearance of the resulting formula object. Note: It is important to realize the difference between X and Y as independent input variables, and the resulting dependent X and Y coordinate values. Depending on the governing formulae they may, or may not, have the same numerical value.

The formula surface object is parameterized as follows: P1-Min ≤ P1 ≤ P1-Max, P2-Min ≤ P2 ≤ P2-Max.

Supported Methods

• Local
• Locate
• Offset
• Point

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Primitive Surface/Solid Objects

The following sections describe basic construction techniques for each of the 3D surface types (and corresponding solid primitives if appropriate) currently supported in StressCheck. It is important to pay particular attention to the definition of the surface coordinate ranges since node definitions are often associated with surfaces using the surface coordinates.

Sphere Object

To create a Sphere object, set the C/A/O/M to Create > Sphere, and choose the desired method (see below for the supported methods).

Overview

A sphere is defined by the coordinates of its center and a radius (Figure 16). The surface coordinates are defined in the range 0 ≤ P1 ≤ 360 (longitude), and -90 ≤ P2 ≤ 90 (latitude). A sphere can be created either as a surface or a solid object by switching between the Surface/Solid Toggle.

Supported Methods

• Delta
• Local
• Locate
• Offset
• Point
• Sample
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Cylinder Object

To create a Cylinder object, set the C/A/O/M to Create > Cylinder, and choose the desired method (see below for the supported methods).

Overview

A cylinder is defined by the coordinates of the center of its base, a radius and a height (Figure 17). The surface coordinates are defined in the range 0 ≤ P1 ≤ 360 (circumferential direction), and 0 ≤ P2 ≤ 1.0 (along the cylinder axis). The P2 coordinate is understood to be a fraction of the defined height of the cylinder.

For example, to place a node on the surface at half the height of the cylinder, the P2 offset parameter should be given as 0.5. In this way, a node will remain at the same relative location on the surface, even when the height of the cylinder is changed. A cylinder can be created either as a surface or a solid object by switching between the Surface/Solid Toggle.

Supported Methods

• Delta
• Local
• Locate
• Offset
• Point
• Sample
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Cone/Frustum Object

To create a Cone/Frustum object, set the C/A/O/M to Create > Cone, and choose the desired method (see below for the supported methods).

Overview

A cone is defined by the coordinates of the center of its base, a base radius (R1), a top radius (R2), and a height (Figure 18).

The surface coordinates are defined in the range 0 ≤ P1 ≤ 360, and 0 ≤ P2 ≤ 1.0. A cone can be created either as a surface or a solid object by switching between the Surface/Solid Toggle.

Supported Methods

• Delta
• Local
• Locate
• Offset
• Point
• Sample
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Torus Object

To create a Torus object, set the C/A/O/M to Create > Torus, and choose the desired method (see below for the supported methods).

Overview

A torus is defined by the coordinates of the center of its base, a major radius (R1), and a minor radius (R2). The surface coordinates are defined in the range 0 ≤ P1 ≤ 360 (along the circumference corresponding to R1), and 0 ≤ P2 ≤ 360 (along the circumference corresponding to R2). These dimensions are illustrated in Figure 19. A torus can be created either as a surface or a solid object by switching between the Surface/Solid Toggle.

Supported Methods

• Delta
• Local
• Locate
• Offset
• Point
• Sample
• Work Plane

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Box Object

To create a Box object, set the C/A/O/M to Create > Box, and choose the desired method (see below for the supported methods).

Overview

A box is defined by the coordinates of the center of its base (X,Y,Z), the width (X-dimension), height (Y-dimension), and depth (Z-dimension). These dimensions are illustrated in Figure 20. A box can be created as either a surface or a solid object by switching between the Surface/Solid Toggle.

A surface box is not a true object, since it may not be edited as a single entity. Once created, it exists only as a collection of points lines and planes. However, it may be created with parametric dimensions, and the underlying objects will respond to changes in the corresponding dimensional parameters. Since the surface box is not a true object, it may not be used as a tool or target in a subsequent boolean or blend operation. If a surface box is defined parametrically, the local system is located at one corner of it. Otherwise, the system is at the same location as for the solid box.

A solid box is a true entity, and may be used as a primitive tool or target in a subsequent boolean, blend or clipping operation. A solid box may be created with parametric dimensions, and may be edited as a single entity.

Supported Methods

• Local
• Locate
• Offset
• Point

Consult the Primitive Geometry Creation Methods section for detailed descriptions.

Tube Object

To create a Tube object, set the C/A/O/M to Create > Tube > Selection.

Overview

A tube is defined by a curved path with a circular cross section defined by R1 (outer radius) and R2 (inner radius). First, create a curve representing the path of the tube (Figure 21a). Next, input the values of R1 and R2. Then, select the curve and the tube will be automatically generated (Figure 21b).

Note: to create a surface tube, set R1=R2. Otherwise, a solid body will be generated.