# Analytical Rigid Surface: Define Tab

Specify the main characteristics of the surface on this tab.

- The Standard3D template enables you to define rigid surfaces of type REVOLUTION and CYLINDER.
- The Standard2D template enables you to define surfaces of type SEGMENTS.
- The Explicit template enables you to define all three types: REVOLUTION, CYLINDER, and SEGMENTS.

You can define the line segments in three different ways, by picking nodes, by picking existing lines, or by manually entering the coordinate values. The options on the Define tab vary according to the type selected.

## SEGMENTS Option

- Plane Definition - Plane/axis
- Abaqus does not require the plane/axis
definition for SEGMENTS type. In HyperMesh, however,
the XY plane must be used for a 2D model. Therefore, the XY plane is
selected by default. If the model is not in the XY plane, you can choose
to select a "User Defined" plane on which the rigid surface should be
defined.
If you choose to manually define the plane/axis, you must enter values for three points (the origin, x axis, and y axis) that define the local coordinate system.

You can also use the following buttons to automatically define the plane in the Local System table:- Pick System...
- Click to select an existing system from the model. Once you select a plane from the model and click proceed, the values are populated in the table.
- Create/Edit System
- Click to create new coordinate systems using the Systems panel.

- Line Definition - No. of line segment datalines
- In this field you specify the number of datalines needed to define the line segments. The actual number of line segments is one less than this number.
- Start by typing the number of datalines needed to define the line segments and click Set. The corresponding number of rows appears in the Line Type table below. In this table, specify the coordinates of the ends of each line segment.
- The first entry in the table is always the START node. This value specifies the beginning point of the first segment. The subsequent segmentsâ€™ starting point is always the end point of the previous segment, or the START node if the segment is the first in the definition.
- For each line type, select a type from the Line Type column: LINE, CIRCL, or PARAB. Each selection activates the appropriate number of columns for the segment definition.
- The segments can be circles, parabolas, or lines. Enter data in the
columns as described below:
- Lines are defined with the x and y coordinates of the end point in the two active columns.
- For circles, specify the x and y coordinate of the end point in the first two columns and then, define the x and y coordinate of the center in the last two columns.
- For parabolas, specify the x and y coordinate of the mid point in the first two columns and then, define the x and y coordinate of the end point in the last two columns. You can also pick nodes or lines from existing geometry using the following buttons:

- Pick Nodes...
- Click to pick nodes from the HyperMesh model for selected line segments. When you click proceed, the coordinate values of the selected nodes will appear in selected line segment cells. In addition, temporary line segments (white color) will also be drawn in the graphic area from the picked nodes. Ensure that you select two nodes in the correct order for circles and parabolas.
- Pick Lines...
- Use this option to define line segments from existing lines
in HyperMesh. These lines must be single
curvature, connected and node1 of a line must be same as
node2 of the previous line.
Click to pick a line from the HyperMesh model. When you click proceed, the coordinate values and line types for the selected lines will appear in the table.

Note: In HyperMesh, the sequence of node1 and node2 for lines can be visualized from the Line Edit/Extend Line panel.

Click Update to update the HyperMesh database with your settings.

## CYLINDER Option

- Plane Definition - Plane/axis
- Choose User Defined if you want to create or select the system, or choose XY, YZ, or XZ to define it in the respective plane.
- If you choose to manually define the plane/axis, you must enter values for three points (the origin, x axis, and generator axis) that define the local plane on which the line segments will be defined.
- You can also use the following buttons to define the plane:
- Pick System...
- Click to select an existing system from the model. Once you select a plane from the model and click proceed, the values are populated in the table.
- Create/Edit System
- Click to create new coordinate systems using the Systems panel.

- Line Definition - No. of line segment datalines
- In this field you specify the number of datalines needed to define the line segments. The actual number of line segments is one less than this number.
- Start by typing the number of segment datalines to define the surface and click Set. The corresponding number of rows appears in the Line Type table below. In this table, specify the coordinates of the ends of each line segment.
- The first entry in the table is always the START node. This value specifies the beginning point of the first segment. The subsequent segmentsâ€™ starting point is always the end point of the previous segment, or the START node if the segment is the first in the definition.
- For each line type, select a type from the Line Type column: LINE, CIRCL, or PARAB. Each selection activates the appropriate number of columns for the segment definition.
- The segments can be circles, parabolas, or lines. Enter data in the
columns as described below:
- Lines are defined with the local x- and local y-coordinates of the end point in the two active columns.
- For circles, specify the local-x and local-y coordinate of the end point in the first two columns and then, define the local-x and local-y coordinate of the center in the last two columns.
- For parabolas, specify the local-x and local-y coordinate of the mid point in the first two columns and then, define the local-x and local-y coordinate of the end point in the last two columns.

Note: The local x- and local y-coordinates must be relative to the plane defined in the Plane/axis table. - You can also pick nodes or lines from existing geometry using the
following buttons:
- Pick Nodes...
- Click to pick nodes from the HyperMesh model for selected line segments. When you click proceed, the coordinate values of the selected nodes will appear in selected line segment cells. In addition, temporary line segments (white color) will also be drawn in the graphic area from the picked nodes. Ensure that you select two nodes in the correct order for circles and parabolas.
- Pick Lines...
- Use this option to define line segments from existing lines
in HyperMesh. These lines must be single
curvature, connected and node1 of a line must be same as
node2 of the previous line.
Click to pick a line from the HyperMesh model. When you click proceed, the coordinate values and line types for the selected lines will appear in the table.

Note: In HyperMesh, the sequence of node1 and node2 for lines can be visualized from the Line Edit/Extend Line panel.

- Line Definition - Sweep Distance
- Abaqus does not need the sweep distance. The CYLINDER type surfaces are swept to infinity in Abaqus. However, in HyperMesh, you must define a sweeping distance to draw the three-dimensional surface. Select the Sweep distance check box to specify a sweep distance and type a value in the adjacent box. Select the Both directions check box to sweep in opposite directions along the generator vector.

Click Update to update the HyperMesh database with your settings.

## REVOLUTION Option

- Plane Definition - Plane/axis
- Choose User Defined if you want to create or select the system, or choose XY, YZ, or XZ to define it in the respective plane.
- If you choose to manually define the axis, you must enter values for two points (the origin and the z axis). Abaqus does not need the x axis values because any plane that passes through the z axis will define the same revolute surface. However, HyperMesh requires the definition of the x (or radial) axis to define the plane on which the line segments are drawn.
- You can also use the following buttons to automatically define the axis
of revolution and x (radial) axis.Note: The coordinate values to define the x axis change if you pick a node (or line) from HyperMesh as the START node.
- Pick System...
- Click to select an existing system from the model. Once you select a plane from the model and click proceed, the values are populated in the table.
- Create/Edit System
- Click to create new coordinate systems using the Systems panel.

- Line Definition - No. of line segment datalines
- In this field you specify the number of datalines needed to define the line segments. The actual number of line segments is one less than this number.
- Start by typing the number of line segment datalines to define the surface and click the Set button. The corresponding number of rows appears in the Line Type table below. In this table, specify the coordinates of the ends of each line segment.
- The first entry in the table is always the START node. This value specifies the beginning point of the first segment. The subsequent segmentsâ€™ starting point is always the end point of the previous segment, or the START node if the segment is the first in the definition.
- For each line type, select a type from the Line Type column: LINE, CIRCL, or PARAB. Each selection activates the appropriate number of columns for the segment definition.
- The segments can be circles, parabolas, or lines. Enter data in the
columns as described below:
- Lines are defined with the local-x (or r) and local-y (or z) coordinates of the end point in the two active columns.
- For circles, specify the local-x (or r) and local-y (or z) coordinate of the end point in the first two columns and then, define the local-x (or r) and local-y (or z) coordinate of the center in the last two columns.
- For parabolas, specify the local-x (or r) and local-y (or z) coordinate of the mid point in the first two columns and then, define the local-x and local-y (or z) coordinate of the end point in the last two columns.

- You can also pick nodes or lines from existing geometry using the
following buttons:
- Pick Nodes...
- Click to pick nodes from the HyperMesh model for selected line segments. When you click proceed, the coordinate values of the selected nodes relative to the defined plane will appear in selected line segment cells. In addition, temporary line segments (white color) will also be drawn in the graphic area from the picked nodes. Ensure that you select two nodes in the correct order for circles and parabolas.
- Pick Lines...
- Click to pick a line from the HyperMesh
model. When you click proceed, the
coordinate values and line types for the selected lines will
appear in the table.Note: In HyperMesh, the sequence of node1 and node2 for lines can be visualized from the Line Edit/Extend Line panel.

- Line Definition - Revolution angle
- Abaqus does not need the revolution angle. The REVOLUTION type surfaces are revolved around 360 degrees in Abaqus. However, in HyperMesh, you must define a revolution angle to draw the three-dimensional surface. Select the Revolution angle check box to specify the angle of revolution and type a value in the adjacent box.

Click Update to update the HyperMesh database with your settings.