When you create a part with wire regions, ABAQUS assigns the default tangent directions to the regions. Beam section orientations depend on the tangent directions. You can reverse the direction of a beam or truss tangent to obtain the desired beam section orientation. You can use the Query toolset to verify that the beam section orientations are correct for a selected region. For more information, see “Using the Query toolset to obtain assignment information,” Section 12.14
To assign a beam/truss tangent direction to a part:
If the part to which you want to assign a tangent is not visible in the current viewport, click the name of the desired part in the Part list located under the toolbar.
The selected part appears in the current viewport.
From the main menu bar, select Assign
Tangent.
Tip:
You can also click the 
tool in the Property module toolbox.
ABAQUS/CAE displays an arrow in the direction of the tangent at the center of each region.
Use one of the following methods to select the regions whose tangents you want to reverse:
Select the regions from the viewport, and click mouse button 2. (For more information, see Chapter 6, “Selecting objects within the viewport.”)
Tip:
You can limit the types of objects that you can select in the viewport by clicking the selection filter tool 
in the prompt area and then clicking the selection filter of your choice in the dialog box that appears. See “Using the selection options,” Section 6.3, for more information.
To select from a list of existing sets, do the following:
Click Sets on the right side of the prompt area.
ABAQUS/CAE displays the Region Selection dialog box containing a list of available part sets.
Select the part set of interest, and click Continue.
Note: The default selection method is based on the selection method you most recently employed. To revert to the other method, click Select in Viewport or Sets on the right side of the prompt area.
Repeat the previous step as often as necessary to reverse additional tangent directions. When you have finished assigning tangent directions, use one of the following methods to exit the assignment mode:
If you are selecting regions of the part from the viewport, click mouse button 2 or click Done in the prompt area.
If you are selecting preexisting sets from the Region Selection dialog box, click Cancel to close the dialog box, then click mouse button 2 or click Done in the prompt area.
