Analysis Solution

The local axis are manipulated with the CATAnalysisExplicitAxis class. This class is build by derivation of CATAnalysisExplicitEntity and have some dedicated methods to convert coordinates system. The associated category of the entity is "AXIS". Three kind of axis definition exist as described after. For each kind, the three points defining the axis can be expressed as coordinates or as existing nodes. An axis is considered as valid if the three points of the definition allow to build a 3D axis, this means points have to be non collinear and non coincident.

The physical types that define the points for an axis based on coordinates are:

• ORIGIN_COORDINATE defines the center.
• LOCAL_XZ_COORDINATE defines a point that lies on the XZ plane.
• LOCAL_Z_COORDINATE defines a point on the Z direction.

A local axis that is defined with coordinates can be defined in another axis system. In this case, the physical type LOCAL_AXIS defines the local axis in which the coordinates are expressed

The physical types that define the points for an axis based on coordinates are:

• ORIGIN_NODE defines the node center.
• LOCAL_XZ_NODE defines a node that lies on the XZ plane.
• LOCAL_Z_NODE defines a node on the Z direction.

Notes:

1. A local axis that is defined with nodes is always expressed in the global axis system.
2. A cylindrical of spherical axis can manage an optional characteristic called "REVERSE". If REVERSE is not valuated the radial direction is defined from the center to the point, else, the direction is defined from the point to the center.

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Cartesian Axis

Two physical types of axes can be used:

For example the point P is is defined by it's coordinates (X, Y, Z) in such a local axis.

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Cylindrical Axis

Two physical types of axes can be used:

For example the point P is is defined by it's coordinates (R, , Z) in such a local axis (defined without reverse).

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Spherical Axis

Two physical types of axes can be used:

For example the point P is is defined by it's coordinates (R, , ) in such a local axis (defined without reverse).

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Guidelines for Creating and Accessing an Axis

To create an axis, to kinds of scenario can be described:

You create a feature that is build by derivation of "AnalysisAxis". In this case you can implement on the feature the CATISamExplicitation Interface that will create an CATAnalysisExplicitAxis inside the field model.

You create a feature that defines some characteristics base on implicit axis defined on a geometry (Cylinder...), in this case you can build in the Field model an entity in which the characteristics will be expressed in a global axis system or in a local axis system.

For the second case, in the implementation of CATISamExplicitation of your entity that we will call EntityXXX in the next lines:

• Create your entity EntityXXX
• Retrieve the ExplicitSet associated to the feature "AxisSet" created by default at the CATAnalysis document initialization. (For this, use CATISamExplicit::GetExplicitObjects() ).
• Create a local axis as an CATAnalysisExplicitEntity with the ExplicitSet retrieved previously, this new entity will be called here EntityAxis
• As child of the EntityXXX, create a characteristic with physical type "LOCAL_AXIS" and valuate this characteristic with the EntityAxis. For this, extract the explicit pointer by using EntityAxis.GetExplicitPointer() and valuate the characteristic with this pointer.
• As children of the EntityXXX, create other required characteristics, and manage the apply on the finite element support.
• At the end of the implementation of CATISamExplicitation, after the UpdateExplicitList, add the local axis created to the "output explicit List". This will allow the local axis to support undo/redo and standard update mechanism.

A standard sample of CATISamExplicitation can be found in the references.

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References

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History

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