You can position a datum point by selecting an edge on the model and entering a parameter value that represents a percentage of the edge length. An arrow along the edge indicates the direction of increasing parameter value from the start vertex (corresponding to an edge parameter value of zero) to the end vertex (corresponding to a value of one.)
To create a datum point by entering an edge parameter:
From the main menu bar, select Tools
Datum.
The Create Datum dialog box appears. The dialog box outlines the types of datum geometry you can create.
ABAQUS/CAE displays prompts in the prompt area to guide you through the procedure.
Tip:
You can also create a datum point using the 
tool, located in the module toolbox. For a diagram of the datum tools in the toolbox, see “Using the Datum toolset,” Section 40.2.
From the list of types at the top of the dialog box, choose Point.
The Method list indicates the methods you can use to create a datum point.
From the Method list, select Enter parameter and click OK.
From the part or assembly in the current viewport, select the edge on which the datum point will be positioned.
An arrow appears on the selected edge indicating the direction of increasing parameter value.
In the text field in the prompt area, enter the value of the edge parameter.
The datum point appears. You can modify the position of the datum point by selecting FeatureEdit from the main menu bar and modifying the value of the edge parameter.
