13. Rigid, Mass, Spring and Gap Elements - RigidElem,MassElem,DiscElem,GapElem

The RigidElem, MassElem, DiscElem and GapElem modules provide for the visualization of rigid, mass, spring and uniaxial gap elements. The objective is to create graphic representations of these "discrete" elements which reveal their detailed element properties. For example mass elements will contain icons for both translational and/or rotational mass, draw any offsets of the mass from the attachment node and label any degree of freedom attachments defined.

An attempt has been made to make the features of the representation of all element types as consistent as possible. The basic representation of an element is dependent upon the topology, element local system, a given special type, and node coordinates. More detailed element properties may be drawn if an EProp element property object is registered as an attribute object.

Table of Contents

13.1 Rigid Elements - RigidElem

Use the RigidElem module to draw various types of rigid elements. The basic element representation is primarily dependent upon the element special type. The special types include distributing couplings, kinematic couplings, inextensional couplings and multipoint constraints. The detailed element properties draw the dependent and independent degrees of freedom at each node and possible weights or coefficients.

The functions associated with a RigidElem object are the following.

Begin and end an instance of an object, return object error flag

*vis_RigidElemBegin       - create an instance of a RigidElem object
vis_RigidElemEnd          - destroy an instance of a RigidElem object
vis_RigidElemError        - return RigidElem object error flag

Set, manipulate and query results

vis_RigidElemCurv         - draw element
vis_RigidElemSetObject    - set pointers to attribute objects
vis_RigidElemSetParamf    - set element display parameters
vis_RigidElemSetParami    - set element display parameters
vis_RigidElemSetSpec      - set special type
vis_RigidElemSetTopology  - set element topology

Instance a RigidElem object using vis_RigidElemBegin. The basic element representation is dependent upon the element topology set using vis_RigidElemSetTopology and the element special type set using vis_RigidElemSetSpec The element is drawn using vis_RigidElemCurv. If the rigid element topology is VIS_SHAPEPOINT then the basic representation connects the first node to each of the subsequent nodes. If the rigid element topology is VIS_SHAPELINE then the basic representation connects the nodes with a line strip. If the rigid element topology is VIS_SHAPETRI or VIS_SHAPEQUAD then the basic representation connects the nodes with a line loop and optionally fills the interior of the line loop. The icon used to connect nodes depends upon the given element special type.

Detailed element properties may be drawn by registering an EProp attribute object using vis_RigidElemSetObject and enabling property drawing using vis_RigidElemSetParami. In this case the element dependent and independent degrees of freedom are labeled and distributing coupling weights or multipoint constraint coefficients are drawn. An option is provided to draw the thickness of distributing couplings dependent upon the weights of each independent node. Use vis_RigidElemSetParami to enable this option and use vis_RigidElemSetParamf to set the sizing factor for unit weight.

Table of Contents

13.2 Attribute Objects

A RigidElem object uses DrawFun, VisContext, ColorMap, TransMap and EProp objects to define attributes to generate an element representation. The DrawFun, VisContext and ColorMap objects are required. The TransMap object is needed only to draw transparent element fill. The EProp object is required only if detailed property drawing is enabled using vis_RigidElemSetParami. A RigidElem object uses the following VisContext components.

AColor: Color of degree of freedom flags raster text
CColor: Color of fill
BitmapSize: Bitmap expansion factor
ElemLoc: Element locations at which element bitmap and pixmap icons are drawn.
ElemRep: Element representation. VIS_ELEMREP_SOLID, VIS_ELEMREP_SEMI and VIS_ELEMREP_LINE draws connections between nodes which are dependent upon the element special type. VIS_ELEMREP_PIXMAP and VIS_ELEMREP_BITMAP draws simple line connections between nodes and places a representative bitmap or pixmap icon at the locations specified by ElemLoc.
Color: Color of line connections.
Fill: Fill flag.
LineWidth: Line width of line connections
MinorColor: Minor color of line connections.
Ratio: Ratio of minor color to color of line connections
Size: Maximum width of rigid icons.
Trans: Fill transparency
Flags: The flag VIS_DOFBACK enables drawing a background on behind the degree of freedom flags raster text.

The rigid element representation is dependent upon the element special type and its properties. Figures 12-1a through 12-1d illustrate the detailed representation using ElemRep set to VIS_ELEMREP_SOLID and a topology set to VIS_SHAPEPOINT for each of the 4 element special types.

The detailed rigid element properties consist of dependent and independent degrees of freedom at each node and possible distributing coupling weights or multipoint constraint coefficients. These properties are drawn using raster text at each applicable node. The independent degrees of freedom are drawn in bold text, the dependent degrees of freedom are drawn in regular text. If distributing coupling weights or multipoint constraint coefficients are defined they are drawn immediately below the degree of freedom flags at each node.

Distributing coupling properties include the distributing weights for each independent node. The element topology should be set to VIS_SHAPEPOINT and the dependent node should be the first node. Figure 12-1a illustrates a distributed coupling with degree of freedom flags and weights.

Figure 12-1a, Distributing Coupling and Properties

Kinematic couplings can be used to represent a number of rigid element topologies. Use VIS_SHAPEPOINT to represent a set of couplings arranged as a set of "spokes" connected to a single independent node. Use VIS_SHAPELINE for a series of couplings. Use VIS_SHAPETRI and VIS_SHAPEQUAD for rigid triangular plates and quadrilaterals. Figure 12-1b illustrates a set of 3 kinematic couplings connected to a single independent node with degree of freedom flags.

Figure 12-1b, Kinematic Coupling and Properties

Links are designed for representing inextensional couplings which usually involve translational freedoms only. The element topology is usually VIS_SHAPEPOINT or VIS_SHAPELINE with 2 points. Figure 12-1c illustrates a single link with degree of freedom flags.

Figure 12-1c, Link and Properties

Multipoint constraints are drawn assuming that the dependent node is the first node. Therefore the topology should be set to VIS_SHAPEPOINT. Figure 12-1d illustrates a multipoint constraint involving 4 nodes.

Figure 12-1d, Multipoint Constraint and Properties

If a rigid element is drawn as a bitmap or pixmap then the basic representation is the same for all special types. The pixmap representation is shown in Figure 12-1e.

Figure 12-1e, Rigid Element as a Pixmap

A kinematic coupling with a topology set to VIS_SHAPEQUAD drawn in the basic representation is illustrated in Figure 12-1f. The element is filled with 50 percent transparency.

Figure 12-1f, Basic Quadrilateral Kinematic Coupling

Table of Contents

13.3 Function Descriptions

The currently available RigidElem functions are described in detail in this section.

Table of Contents , RigidElem

NAME

*vis_RigidElemBegin - create an instance of an RigidElem object

C SPECIFICATION

vis_RigidElem *vis_RigidElemBegin ()

ARGUMENTS

None

FUNCTION RETURN VALUE

The function returns a pointer to the newly created RigidElem object. If the object creation fails, NULL is returned.

DESCRIPTION

Create an instance of an RigidElem object. Memory is allocated for the object private data and the pointer to the data is returned. By default all attribute object pointers are NULL.

Destroy an instance of a RigidElem object using

     void vis_RigidElemEnd (vis_RigidElem *rigidelem)

Return the current value of a RigidElem object error flag using

     Vint vis_RigidElemError (vis_RigidElem *rigidelem)

Table of Contents , RigidElem

NAME

vis_RigidElemCurv - draw element

C SPECIFICATION

void vis_RigidElemCurv (vis_RigidElem *rigidelem,
                        Vfloat x[][3])

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
x            Array of node locations defining element connections.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_NULLOBJECT is generated if required attribute objects have not been set using vis_RigidElemSetObject.

DESCRIPTION

Draw a rigid element with node points, x.

Table of Contents , RigidElem

NAME

vis_RigidElemSetObject - set pointers to attribute objects

C SPECIFICATION

void vis_RigidElemSetObject (vis_RigidElem *rigidelem,
                             Vint objecttype,
                             Vobject *object)

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
objecttype   The name of the object type to be set.
             =VIS_COLORMAP           ColorMap object
             =VGL_DRAWFUN            DrawFun object
             =VIS_TRANSMAP           TransMap object
             =VIS_VISCONTEXT         VisContext object
             =VIS_EPROP              EProp object
object       Pointer to the object to be set.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_OBJECTTYPE is generated if an improper objecttype is specified.

DESCRIPTION

Set a pointer to an attribute object.

Table of Contents , RigidElem

NAME

vis_RigidElemSetParamf - set element display parameters

C SPECIFICATION

void vis_RigidElemSetParamf (vis_RigidElem *rigidelem,
                             Vint ptype,
                             Vfloat fparam)

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
ptype        Type of display parameter to set
             =RIGIDELEM_WGTSIZE      Size of unit weight
fparam       Specifies the value that ptype will be set to.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper ptype is specified. VIS_ERROR_VALUE is generated if an improper fparam is specified.

DESCRIPTION

Set element display parameters.

The parameter RIGIDELEM_WGTSIZE sets the size of a unit weight. Use vis_RigidElemSetParami to enable weight sizing and detailed element properties. By default RIGIDELEM_WGTSIZE is set 1.

Table of Contents , RigidElem

NAME

vis_RigidElemSetParami - set element display parameters

C SPECIFICATION

void vis_RigidElemSetParami (vis_RigidElem *rigidelem,
                             Vint ptype,
                             Vint iparam)

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
ptype        Type of display parameter to set
             =RIGIDELEM_PROP         Draw detailed properties
             =RIGIDELEM_WGTSIZEFLAG  Weight sizing flag
iparam       Specifies the integer value that ptype will be set to.
             =VIS_OFF                Turn parameter off
             =VIS_ON                 Turn parameter on

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper ptype is specified.

DESCRIPTION

Set element display parameters. The parameter RIGIDELEM_PROP enables drawing detailed element properties contained in the EProp attribute object. By default RIGIDELEM_PROP is set to VIS_OFF.

The parameter RIGIDELEM_WGTSIZEFLAG enables drawing the sizing of distributing couplings proportionately to the weights at each independent node. Use vis_RigidElemSetParamf to set the size of unit weight. By default RIGIDELEM_WGTSIZEFLAG is set to VIS_OFF.

Table of Contents , RigidElem

NAME

vis_RigidElemSetSpec - set special type

C SPECIFICATION

void vis_RigidElemSetSpec (vis_RigidElem *rigidelem,
                           Vint spec)

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
spec         Element special type
             =SYS_RIGID_KINE         Kinematic coupling
             =SYS_RIGID_DIST         Distributing coupling
             =SYS_RIGID_JOINT        Joint constraint
             =SYS_RIGID_LINK         Inextensional coupling
             =SYS_RIGID_MPC          Multipoint constraint
             =SYS_RIGID_RBE3         Interpolation constraint
             =SYS_RIGID_SPLINE       Spline constraint

OUTPUT ARGUMENTS

None

DESCRIPTION

Set element special type. By default spec is set to SYS_RIGID_KINE. The types SYS_RIGID_DIST and SYS_RIGID_RBE3 are drawn identically.

Table of Contents , RigidElem

NAME

vis_RigidElemSetTopology - set element topology

C SPECIFICATION

void vis_RigidElemSetTopology (vis_RigidElem *rigidelem,
                               Vint shape,
                               Vint maxi)

INPUT ARGUMENTS

rigidelem    Pointer to RigidElem object.
shape        Element shape parameter
             =VIS_SHAPEPOINT         Point
             =VIS_SHAPELINE          Line
             =VIS_SHAPETRI           Triangle
             =VIS_SHAPEQUAD          Quadrilateral
maxi         The number of points along the i direction.
             If maxi = 0 then the linear
             element form of the specified shape is assumed.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_VALUE is generated if an improper maxi is input. VIS_ERROR_ENUM is generated if an improper shape is input.

DESCRIPTION

Set element topology. For triangle and quadrilateral shapes maxi = 0 or 2 and Serendipity element node connectivity convention is assumed. See section VisTools, Computational Cells for a description of element topology conventions.

Table of Contents

13.4 Mass Elements - MassElem

Use the MassElem module to draw various types of mass elements. The basic element representation is primarily dependent upon the element special type. The special types include scalar mass, lumped mass, and mass matrix. The detailed element properties draw icons for translational and/or rotational mass, mass offset and degree of freedom attachments.

The functions associated with a MassElem object are the following.

Begin and end an instance of an object, return object error flag

*vis_MassElemBegin       - create an instance of a MassElem object
vis_MassElemEnd          - destroy an instance of a MassElem object
vis_MassElemError        - return MassElem object error flag

Set, manipulate and query results

vis_MassElemCurv           - draw element
vis_MassElemSetLocalSystem - set local coordinate system convention
vis_MassElemSetObject      - set pointers to attribute objects
vis_MassElemSetParami      - set element display parameters
vis_MassElemSetSpec        - set special type
vis_MassElemSetTopology    - set element topology

Instance a MassElem object using vis_MassElemBegin. The basic element representation is dependent upon the element topology set using vis_MassElemSetTopology, the element special type set using vis_MassElemSetSpec and the element local system set using vis_MassElemSetLocalSystem. The element is drawn using vis_MassElemCurv. A mass element topology is restricted to VIS_SHAPEPOINT with one or two nodes and VIS_SHAPELINE with two nodes only.

Detailed element properties may be drawn by registering an EProp attribute object using vis_MassElemSetObject and enabling property drawing using vis_MassElemSetParami. In this case the element icons are drawn depending upon the existence of translational and/or rotational mass. In addition any offset of the mass from the attachment node is drawn. and any defined degree of freedom attachments are labeled.

Table of Contents

13.5 Attribute Objects

A MassElem object uses DrawFun, VisContext, ColorMap and EProp objects to define attributes to generate an element representation. The DrawFun, VisContext and ColorMap objects are required. The EProp object is required only if detailed property drawing is enabled using vis_MassElemSetParami. A MassElem object uses the following VisContext components.

AColor: Color of degree of freedom flags raster text
BitmapSize: Bitmap expansion factor
ElemAxes: Element local coordinate system axes flags
ElemRep: Element representation. VIS_ELEMREP_SOLID, VIS_ELEMREP_SEMI and VIS_ELEMREP_LINE draws simple line connections between nodes and a three dimensional element icon at the element centroid. VIS_ELEMREP_PIXMAP and VIS_ELEMREP_BITMAP draws simple line connections between nodes and a representative bitmap or pixmap icon at the element centroid.
Color: Color of line connections and mass icon.
Fill: Fill flag.
LineWidth: Line width of mass offset.
LineStyle: Line style of mass offset.
MinorColor: Color of rotational mass and mass offset.
Ratio: The length of the vector head relative to the total length of the vector of rotational mass icon.
Refinement: Level of refinement
Shade: Flag to apply light source shading
Size: Size of mass icons and length of coordinate system axes.
Flags: The flag VIS_DOFBACK enables drawing a background on behind the degree of freedom flags raster text.
XColor: Color of coordinate system x axes
YColor: Color of coordinate system y axes
ZColor: Color of coordinate system z axes

The mass element representation is generally dependent upon the element special type and its properties. Figures 12-2a through 12-2c illustrate the detailed representation using ElemRep set to VIS_ELEMREP_SOLID and a topology set to VIS_SHAPEPOINT for each of the 3 element special types.

The detailed mass element properties consist of the existence of translational and/or rotational mass, mass offset and any defined degree of freedom attachments. The degree of freedom attachments are drawn using raster text at each applicable node. The properties drawn depend upon the element special type.

Scalar mass properties include the degree of freedom attachments only. Figure 12-2a illustrates a scalar mass with these properties. A BitmapSize of 2 is used. An element local system is not applicable.

Figure 12-2a, Scalar Mass and Properties

Lumped mass properties include translational and/or rotational mass and mass offset. Figure 12-2b illustrates a lumped mass with these properties. An element local system is drawn.

Figure 12-2b, Lumped Mass and Properties

The mass matrix representation does not depend on the element properties. Figure 12-2c illustrates a mass matrix. An element local system is drawn.

Figure 12-2c, Mass Matrix

Table of Contents

13.6 Function Descriptions

The currently available MassElem functions are described in detail in this section.

Table of Contents , MassElem

NAME

*vis_MassElemBegin - create an instance of an MassElem object

C SPECIFICATION

vis_MassElem *vis_MassElemBegin ()

ARGUMENTS

None

FUNCTION RETURN VALUE

The function returns a pointer to the newly created MassElem object. If the object creation fails, NULL is returned.

DESCRIPTION

Create an instance of an MassElem object. Memory is allocated for the object private data and the pointer to the data is returned. By default all attribute object pointers are NULL.

Destroy an instance of a MassElem object using

     void vis_MassElemEnd (vis_MassElem *masselem)

Return the current value of a MassElem object error flag using

     Vint vis_MassElemError (vis_MassElem *masselem)

Table of Contents , MassElem

NAME

vis_MassElemCurv - draw element

C SPECIFICATION

void vis_MassElemCurv (vis_MassElem *masselem,
                       Vfloat x[][3])

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
x            Array of node locations defining element connections.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_NULLOBJECT is generated if required attribute objects have not been set using vis_MassElemSetObject.

DESCRIPTION

Draw a mass element with node points, x.

Table of Contents , MassElem

NAME

vis_MassElemSetLocalSystem - set local coordinate system convention

C SPECIFICATION

void vis_MassElemSetLocalSystem (vis_MassElem *masselem,
                                 Vint type,
                                 Vfloat vec[],
                                 Vfloat angle)

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
type         Local system convention
             =SYS_ELEMSYS_STANDARD   Standard orientation
             =SYS_ELEMSYS_POSITION   Orient to position vector
             =SYS_ELEMSYS_GLOBAL     Global axis
             =SYS_ELEMSYS_GLOBALPROJECT  Orient to global axis projection
             =SYS_ELEMSYS_GLOBALCLOSEST  Orient to closest global axis
             =SYS_ELEMSYS_VECTOR     Orient to direction vector
             =SYS_ELEMSYS_ROTANG     Orient to rotation angle vector
             =SYS_ELEMSYS_BISECTOR   Orient to element bisector
vec          Orientation position, direction or normal vector(s)
angle        Angle to rotate element y',z' axes about the element x'
             axis in degrees.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper type is input.

DESCRIPTION

Specify the convention to be used to construct the orientation of the mass element. Note that if the element consists of a single node or two coincident nodes then the local system must be SYS_ELEMSYS_GLOBAL or SYS_ELEMSYS_ROTANG. By default type is SYS_ELEMSYS_GLOBAL and angle is zero.

Table of Contents , MassElem

NAME

vis_MassElemSetObject - set pointers to attribute objects

C SPECIFICATION

void vis_MassElemSetObject (vis_MassElem *masselem,
                            Vint objecttype,
                            Vobject *object)

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
objecttype   The name of the object type to be set.
             =VIS_COLORMAP           ColorMap object
             =VGL_DRAWFUN            DrawFun object
             =VIS_VISCONTEXT         VisContext object
             =VIS_EPROP              EProp object
object       Pointer to the object to be set.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_OBJECTTYPE is generated if an improper objecttype is specified.

DESCRIPTION

Set a pointer to an attribute object.

Table of Contents , MassElem

NAME

vis_MassElemSetParami - set element display parameters

C SPECIFICATION

void vis_MassElemSetParami (vis_MassElem *masselem,
                            Vint ptype,
                            Vint iparam)

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
ptype        Type of display parameter to set
             =MASSELEM_PROP          Draw detailed properties
             =MASSELEM_CHECKER       Draw checkered cube mass matrix
iparam       Specifies the integer value that ptype will be set to.
             =VIS_OFF                Turn parameter off
             =VIS_ON                 Turn parameter on

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper ptype is specified.

DESCRIPTION

Set element display parameters.

The parameter MASSELEM_PROP enables drawing detailed element properties contained in the EProp attribute object. By default MASSELEM_PROP is set to VIS_OFF.

The parameter MASSELEM_CHECKER enables drawing a mass matrix element as a checkered cube. If disabled, a mass matrix is drawn as an "edged" cube. By default MASSELEM_CHECKER is set to VIS_OFF.

Table of Contents , MassElem

NAME

vis_MassElemSetSpec - set special type

C SPECIFICATION

void vis_MassElemSetSpec (vis_MassElem *masselem,
                          Vint spec)

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
spec         Element special type
             =SYS_MASS_SCALAR        Scalar mass
             =SYS_MASS_LUMP          Lumped mass
             =SYS_MASS_MATRIX        Mass matrix

OUTPUT ARGUMENTS

None

DESCRIPTION

Set element special type. By default spec is set to SYS_MASS_SCALAR.

Table of Contents , MassElem

NAME

vis_MassElemSetTopology - set element topology

C SPECIFICATION

void vis_MassElemSetTopology (vis_MassElem *masselem,
                              Vint shape,
                              Vint maxi)

INPUT ARGUMENTS

masselem     Pointer to MassElem object.
shape        Element shape parameter
             =VIS_SHAPEPOINT         Point
             =VIS_SHAPELINE          Line
maxi         The number of points along the i direction.
             If maxi = 0 then the linear
             element form of the specified shape is assumed.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_VALUE is generated if an improper maxi is input. VIS_ERROR_ENUM is generated if an improper shape is input.

DESCRIPTION

Set element topology. For line shapes, maxi must equal 0 or 2. See section VisTools, Computational Cells for a description of element topology conventions.

Table of Contents

13.7 Spring and Dashpot Elements - DiscElem

Use the DiscElem module to draw various types of spring and dashpot elements. The basic element representation is primarily dependent upon the element special type. The special types include scalar spring and dashpot, link, spot weld, and bushing. The detailed element properties draw icons for translational and/or rotational stiffness, damping and degree of freedom attachments.

The functions associated with a DiscElem object are the following.

Begin and end an instance of an object, return object error flag

*vis_DiscElemBegin       - create an instance of a DiscElem object
vis_DiscElemEnd          - destroy an instance of a DiscElem object
vis_DiscElemError        - return DiscElem object error flag

Set, manipulate and query results

vis_DiscElemCurv           - draw element
vis_DiscElemSetLocalSystem - set local coordinate system convention
vis_DiscElemSetObject      - set pointers to attribute objects
vis_DiscElemSetParami      - set element display parameters
vis_DiscElemSetSpec        - set special type
vis_DiscElemSetTopology    - set element topology

Instance a DiscElem object using vis_DiscElemBegin. The basic element representation is dependent upon the element topology set using vis_DiscElemSetTopology, the element special type set using vis_DiscElemSetSpec and the element local system set using vis_DiscElemSetLocalSystem. The element is drawn using vis_DiscElemCurv. A spring element topology is restricted to VIS_SHAPEPOINT with any number of nodes and VIS_SHAPELINE with two nodes only.

Detailed element properties may be drawn by registering an EProp attribute object using vis_DiscElemSetObject and enabling property drawing using vis_DiscElemSetParami. In this case the element icons are drawn depending upon the existence of translational and/or rotational stiffness and damping. Any defined degree of freedom attachments are labeled.

Table of Contents

13.8 Attribute Objects

A DiscElem object uses DrawFun, VisContext, ColorMap and EProp objects to define attributes to generate an element representation. The DrawFun, VisContext and ColorMap objects are required. The EProp object is required only if detailed property drawing is enabled using vis_DiscElemSetParami. A DiscElem object uses the following VisContext components.

AColor: Color of degree of freedom flags raster text
BitmapSize: Bitmap expansion factor
ElemAxes: Element local coordinate system axes flags
ElemRep: Element representation. VIS_ELEMREP_SOLID, VIS_ELEMREP_SEMI and VIS_ELEMREP_LINE draws simple line connections between nodes and a three dimensional element icon at the element centroid. VIS_ELEMREP_PIXMAP and VIS_ELEMREP_BITMAP draws simple line connections between nodes and a representative bitmap or pixmap icon at the element centroid.
Color: Color of line connections and spring icon.
Fill: Fill flag.
MinorColor: Color of ground icon
Refinement: Level of refinement
Shade: Flag to apply light source shading
Size: Size of spring icons and length of coordinate system axes.
XColor: Color of coordinate system x axes
YColor: Color of coordinate system y axes
ZColor: Color of coordinate system z axes

The spring element representation is dependent upon the element topology, special type and its properties. Figures 12-3a through 12-3d illustrate the detailed representation using ElemRep set to VIS_ELEMREP_SOLID and a topology set to VIS_SHAPEPOINT for each of the 4 element special types.

Scalar spring properties include the degree of freedom attachments only. Figure 12-3a illustrates a scalar spring with these properties. A BitmapSize of 2 is used. An element local system is not applicable.

Figure 12-3a, Scalar Spring and Properties

The link spring and dashpot properties include the existence of stiffness and/or damping coefficients. Figure 12-3b illustrates a scalar spring and and dashpot. An element local system is drawn

Figure 12-3b, Link Spring and Dashpot

The weld spring properties include the diameter. The icon is a cylinder of the specified diameter. Figure 12-3c illustrates a weld spring. An element local system is drawn

Figure 12-3c, Weld Spring

The bush spring properties include spring stiffnesses in each of 3 translational and 3 rotational directions. Figure 12-3d illustrates a bush spring. An element local system is drawn

Figure 12-3d, Bush Spring

Table of Contents

13.9 Function Descriptions

The currently available DiscElem functions are described in detail in this section.

Table of Contents , DiscElem

NAME

*vis_DiscElemBegin - create an instance of an DiscElem object

C SPECIFICATION

vis_DiscElem *vis_DiscElemBegin ()

ARGUMENTS

None

FUNCTION RETURN VALUE

The function returns a pointer to the newly created DiscElem object. If the object creation fails, NULL is returned.

DESCRIPTION

Create an instance of an DiscElem object. Memory is allocated for the object private data and the pointer to the data is returned. By default all attribute object pointers are NULL.

Destroy an instance of a DiscElem object using

     void vis_DiscElemEnd (vis_DiscElem *discelem)

Return the current value of a DiscElem object error flag using

     Vint vis_DiscElemError (vis_DiscElem *discelem)

Table of Contents , DiscElem

NAME

vis_DiscElemCurv - draw element

C SPECIFICATION

void vis_DiscElemCurv (vis_DiscElem *discelem,
                       Vfloat x[][3])

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
x            Array of node locations defining element connections.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_NULLOBJECT is generated if required attribute objects have not been set using vis_DiscElemSetObject.

DESCRIPTION

Draw a spring element with node points, x.

Table of Contents , DiscElem

NAME

vis_DiscElemSetLocalSystem - set local coordinate system convention

C SPECIFICATION

void vis_DiscElemSetLocalSystem (vis_DiscElem *discelem,
                                 Vint type,
                                 Vfloat vec[],
                                 Vfloat angle)

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
type         Local system convention
             =SYS_ELEMSYS_STANDARD   Standard orientation
             =SYS_ELEMSYS_POSITION   Orient to position vector
             =SYS_ELEMSYS_GLOBAL     Global axis
             =SYS_ELEMSYS_GLOBALPROJECT  Orient to global axis projection
             =SYS_ELEMSYS_GLOBALCLOSEST  Orient to closest global axis
             =SYS_ELEMSYS_VECTOR     Orient to direction vector
             =SYS_ELEMSYS_ROTANG     Orient to rotation angle vector
             =SYS_ELEMSYS_BISECTOR   Orient to element bisector
vec          Orientation position, direction or normal vector(s)
angle        Angle to rotate element y',z' axes about the element x'
             axis in degrees.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper type is input.

DESCRIPTION

Specify the convention to be used to construct the orientation of the spring element. Note that if the element consists of a single node or two coincident nodes then the local system must be SYS_ELEMSYS_GLOBAL or SYS_ELEMSYS_ROTANG. By default type is SYS_ELEMSYS_GLOBALCLOSEST and angle is zero.

Table of Contents , DiscElem

NAME

vis_DiscElemSetObject - set pointers to attribute objects

C SPECIFICATION

void vis_DiscElemSetObject (vis_DiscElem *discelem,
                            Vint objecttype,
                            Vobject *object)

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
objecttype   The name of the object type to be set.
             =VIS_COLORMAP           ColorMap object
             =VGL_DRAWFUN            DrawFun object
             =VIS_VISCONTEXT         VisContext object
             =VIS_EPROP              EProp object
object       Pointer to the object to be set.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_OBJECTTYPE is generated if an improper objecttype is specified.

DESCRIPTION

Set a pointer to an attribute object.

Table of Contents , DiscElem

NAME

vis_DiscElemSetParami - set element display parameters

C SPECIFICATION

void vis_DiscElemSetParami (vis_DiscElem *discelem,
                            Vint ptype,
                            Vint iparam)

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
ptype        Type of display parameter to set
             =DISCELEM_PROP          Draw detailed properties
iparam       Specifies the integer value that ptype will be set to.
             =VIS_OFF                Turn parameter off
             =VIS_ON                 Turn parameter on

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper ptype is specified.

DESCRIPTION

Set element display parameters. The parameter DISCELEM_PROP enables drawing detailed element properties contained in the EProp attribute object. By default DISCELEM_PROP is set to VIS_OFF.

Table of Contents , DiscElem

NAME

vis_DiscElemSetSpec - set special type

C SPECIFICATION

void vis_DiscElemSetSpec (vis_DiscElem *discelem,
                          Vint spec)

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
spec         Element special type
             =SYS_SPRINGDASHPOT_SCALAR Scalar springdashpot
             =SYS_SPRINGDASHPOT_LINK   Link
             =SYS_SPRINGDASHPOT_WELD   Spot weld
             =SYS_SPRINGDASHPOT_BUSH   Bushing

OUTPUT ARGUMENTS

None

DESCRIPTION

Set element special type. By default spec is set to SYS_SPRINGDASHPOT_SCALAR.

Table of Contents , DiscElem

NAME

vis_DiscElemSetTopology - set element topology

C SPECIFICATION

void vis_DiscElemSetTopology (vis_DiscElem *discelem,
                              Vint shape,
                              Vint maxi)

INPUT ARGUMENTS

discelem     Pointer to DiscElem object.
shape        Element shape parameter
             =VIS_SHAPEPOINT         Point
             =VIS_SHAPELINE          Line
maxi         The number of points along the i direction.
             If maxi = 0 then the linear
             element form of the specified shape is assumed.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_VALUE is generated if an improper maxi is input. VIS_ERROR_ENUM is generated if an improper shape is input.

DESCRIPTION

Set element topology. For line shapes, maxi must equal 0 or 2. See section VisTools, Computational Cells for a description of element topology conventions.

Table of Contents

13.10 Gap Elements - GapElem

Use the GapElem module to draw uniaxial gap elements. There are currently no special types for gap elements. The detailed element properties include representing the initial gap.

The functions associated with a GapElem object are the following.

Begin and end an instance of an object, return object error flag

*vis_GapElemBegin       - create an instance of a GapElem object
vis_GapElemEnd          - destroy an instance of a GapElem object
vis_GapElemError        - return GapElem object error flag

Set, manipulate and query results

vis_GapElemCurv           - draw element
vis_GapElemSetLocalSystem - set local coordinate system convention
vis_GapElemSetObject      - set pointers to attribute objects
vis_GapElemSetParami      - set element display parameters
vis_GapElemSetTopology    - set element topology

Instance a GapElem object using vis_GapElemBegin. The basic element representation is dependent upon the element topology set using vis_GapElemSetTopology and the element local system set using vis_GapElemSetLocalSystem. The element is drawn using vis_GapElemCurv. A gap element topology is restricted to VIS_SHAPEPOINT with one or two nodes and VIS_SHAPELINE with two nodes only. A gap element with a single node is assumed to be a node to ground gap, a special ground icon is included in the gap element representation.

Detailed element properties may be drawn by registering an EProp attribute object using vis_GapElemSetObject and enabling property drawing using vis_GapElemSetParami. In this case the gap element initial gap is represented exactly in the spacing of the gap element icons.

Table of Contents

13.11 Attribute Objects

A GapElem object uses DrawFun, VisContext, ColorMap and EProp objects to define attributes to generate an element representation. The DrawFun, VisContext and ColorMap objects are required. The EProp object is required only if detailed property drawing is enabled using vis_GapElemSetParami. A GapElem object uses the following VisContext components.

AColor: Color of degree of freedom flags raster text
BitmapSize: Bitmap expansion factor
ElemAxes: Element local coordinate system axes flags
ElemRep: Element representation. VIS_ELEMREP_SOLID, VIS_ELEMREP_SEMI and VIS_ELEMREP_LINE draws simple line connections between nodes and a three dimensional element icon at the element centroid. VIS_ELEMREP_PIXMAP and VIS_ELEMREP_BITMAP draws simple line connections between nodes and a representative bitmap or pixmap icon at the element centroid.
Color: Color of line connections and gap icon.
Fill: Fill flag.
MinorColor: Color of ground icon
Refinement: Level of refinement
Shade: Flag to apply light source shading
Size: Size of gap icons and length of coordinate system axes.
XColor: Color of coordinate system x axes
YColor: Color of coordinate system y axes
ZColor: Color of coordinate system z axes

The gap element representation is dependent upon the element topology and its properties. Figures 12-4a and 12-4b illustrate the point to point gap and the point to ground gap using ElemRep set to VIS_ELEMREP_SOLID. The detailed gap element properties consist of the initial gap.

The point to point gap orients the gap icon along the element x' coordinate system which may, in general, not necessarily be aligned between the node connections. Figure 12-4a illustrates a point to point gap. An element local system is drawn.

Figure 12-4a, Point to Point Gap

The point to ground gap orients the gap icon along the element x' coordinate system. Figure 12-4b illustrates a point to ground gap. An element local system is drawn.

Figure 12-4b, Point to Ground Gap

Table of Contents

13.12 Function Descriptions

The currently available GapElem functions are described in detail in this section.

Table of Contents , GapElem

NAME

*vis_GapElemBegin - create an instance of an GapElem object

C SPECIFICATION

vis_GapElem *vis_GapElemBegin ()

ARGUMENTS

None

FUNCTION RETURN VALUE

The function returns a pointer to the newly created GapElem object. If the object creation fails, NULL is returned.

DESCRIPTION

Create an instance of an GapElem object. Memory is allocated for the object private data and the pointer to the data is returned. By default all attribute object pointers are NULL.

Destroy an instance of a GapElem object using

     void vis_GapElemEnd (vis_GapElem *gapelem)

Return the current value of a GapElem object error flag using

     Vint vis_GapElemError (vis_GapElem *gapelem)

Table of Contents , GapElem

NAME

vis_GapElemCurv - draw element

C SPECIFICATION

void vis_GapElemCurv (vis_GapElem *gapelem,
                      Vfloat x[][3])

INPUT ARGUMENTS

gapelem      Pointer to GapElem object.
x            Array of node locations defining element connections.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_NULLOBJECT is generated if required attribute objects have not been set using vis_GapElemSetObject.

DESCRIPTION

Draw a gap element with node points, x.

Table of Contents , GapElem

NAME

vis_GapElemSetLocalSystem - set local coordinate system convention

C SPECIFICATION

void vis_GapElemSetLocalSystem (vis_GapElem *gapelem,
                                Vint type,
                                Vfloat vec[],
                                Vfloat angle)

INPUT ARGUMENTS

gapelem      Pointer to GapElem object.
type         Local system convention
             =SYS_ELEMSYS_STANDARD   Standard orientation
             =SYS_ELEMSYS_POSITION   Orient to position vector
             =SYS_ELEMSYS_GLOBAL     Global axis
             =SYS_ELEMSYS_GLOBALPROJECT  Orient to global axis projection
             =SYS_ELEMSYS_GLOBALCLOSEST  Orient to closest global axis
             =SYS_ELEMSYS_VECTOR     Orient to direction vector
             =SYS_ELEMSYS_ROTANG     Orient to rotation angle vector
             =SYS_ELEMSYS_BISECTOR   Orient to element bisector
vec          Orientation position, direction or normal vector(s)
angle        Angle to rotate element y',z' axes about the element x'
             axis in degrees.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper type is input.

DESCRIPTION

Specify the convention to be used to construct the orientation of the gap element. Note that if the element consists of a single node or two coincident nodes then the local system must be SYS_ELEMSYS_GLOBAL or SYS_ELEMSYS_ROTANG. By default type is SYS_ELEMSYS_GLOBALCLOSEST and angle is zero.

Table of Contents , GapElem

NAME

vis_GapElemSetObject - set pointers to attribute objects

C SPECIFICATION

void vis_GapElemSetObject (vis_GapElem *gapelem,
                           Vint objecttype,
                           Vobject *object)

INPUT ARGUMENTS

gapelem      Pointer to GapElem object.
objecttype   The name of the object type to be set.
             =VIS_COLORMAP           ColorMap object
             =VGL_DRAWFUN            DrawFun object
             =VIS_VISCONTEXT         VisContext object
             =VIS_EPROP              EProp object
object       Pointer to the object to be set.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_OBJECTTYPE is generated if an improper objecttype is specified.

DESCRIPTION

Set a pointer to an attribute object.

Table of Contents , GapElem

NAME

vis_GapElemSetParami - set element display parameters

C SPECIFICATION

void vis_GapElemSetParami (vis_GapElem *gapelem,
                           Vint ptype,
                           Vint iparam)

INPUT ARGUMENTS

gapelem      Pointer to GapElem object.
ptype        Type of display parameter to set
             =GAPELEM_PROP           Draw detailed properties
iparam       Specifies the integer value that ptype will be set to.
             =VIS_OFF                Turn parameter off
             =VIS_ON                 Turn parameter on

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_ENUM is generated if an improper ptype is specified.

DESCRIPTION

Set element display parameters. The parameter GAPELEM_PROP enables drawing detailed element properties contained in the EProp attribute object. By default GAPELEM_PROP is set to VIS_OFF.

Table of Contents , GapElem

NAME

vis_GapElemSetTopology - set element topology

C SPECIFICATION

void vis_GapElemSetTopology (vis_GapElem *gapelem,
                             Vint shape,
                             Vint maxi)

INPUT ARGUMENTS

gapelem      Pointer to GapElem object.
shape        Element shape parameter
             =VIS_SHAPEPOINT         Point
             =VIS_SHAPELINE          Line
maxi         The number of points along the i direction.
             If maxi = 0 then the linear
             element form of the specified shape is assumed.

OUTPUT ARGUMENTS

None

ERRORS

VIS_ERROR_VALUE is generated if an improper maxi is input. VIS_ERROR_ENUM is generated if an improper shape is input.

DESCRIPTION

Set element topology. For line shapes, maxi must equal 0 or 2. See section VisTools, Computational Cells for a description of element topology conventions.