After creating a local coordinate system, you can further designate it as being associative or non-associative using the properties of the Origin category in the Details.
An associative coordinate system is joined to a geometry or mesh scoping throughout preprocessing. Therefore, its position and orientation can be affected by geometry updates, part transformation, as well as through the use of the tool (for joints). However, the coordinate system maintains its position throughout the solution process regardless of changes to the geometry as a result of loading.
A non-associative coordinate system is independent of any geometry.
Specify Associative Coordinate System
To establish the origin for an associative coordinate system:
Set the Define By property to either Geometry Selection (default) or .
For a Reference Coordinate System attached to a joint, use the Orientation About Principal Axis category to make the coordinate system associative.
If you select:
Geometry Selection: Select the desired geometry or mesh entities.
Select the Click to Change option in the Geometry property.
Click Apply. A coordinate system symbol displays at the centroid of your selection. The application calculates the centroid of your coordinate system based on a weighted (by volume, area, or length) average for the specified scoping, including:
For Solid bodies and solid body elements, the application calculates the weighted average using the volume of the bodies/elements.
Surface bodies, faces, surface body elements, and element faces, the application calculates the weighted average using the area of the surfaces/surface elements.
Line bodies, edges, and line body elements, the application calculates the weighted average using the length of the line bodies/edges/line elements.
: Select a user-defined Named Selection from the property.
Tip: You can automatically specify the Geometry of a Coordinate System object by first selecting geometry or mesh entities and then inserting a new Coordinate System object.
Note: To create a coordinate system on a Line Body, you need to select one or more edges, vertices, nodes, or elements so that the origin is placed at the centroid of the selections.
Specify Non-Associative Coordinate System
To establish the origin for a non-associative coordinate system:
Set the Define By property to Global Coordinates. You then define the origin in either of the following ways:
Selecting a point on the exterior of the model using the option:
Set the Define By property to Global Coordinates.
Select the Click to Change field of the Location property.
Select the (
) button on the Graphics
Toolbar. This option displays coordinates as you move the cursor across
the model.Select the desired origin location on the model. A small cross hair appears at the selected location.
Click in the Location property field. A coordinate system symbol displays at the origin location. Note that the coordinate values automatically populate the Origin X, Origin Y, and Origin Z properties. You can manually change the location of the coordinate system by changing these values.
Selecting one or more vertices, nodes, element faces, or elements to define an averaged location of selected geometry or mesh entities:
Set the Define By property to Global Coordinates.
Select the Click to Change field of the Location property.
Select the filter (Vertex, Node, Element Face, or Element) on the Graphics Toolbar.
Select as many vertices, nodes, element faces, or elements as desired and then click the option of the Location property. The origin coordinate system is specified on the model based on the average location of the selected entities.
Entering the coordinates directly:
Set Define By to Global Coordinates.
Enter values in the Origin X, Origin Y, and Origin Z properties.