In a Work Plane node’s Plane Geometry sequence you can add a Cross Section node (
). By default, this computes the cross section of all 3D objects generated by preceding nodes in the geometry sequence. You can also select specific 3D objects to intersect with the work plane. You can also add a new 2D or 2D axisymmetric Component and add the Cross Section node there. In that case, you can select which Work Plane to use. For example, if you have a 3D geometry that is symmetric about an axis, you can add a work plane that contains the axis. In the axisymmetric 2D Component, you then get the cross section and can use a 2D axisymmetric component, which is computationally efficient compared to a full 3D component. A Cross Section node can also be useful to extract a planar surface for modeling a thin flat 3D structure using shell elements, for example. To add a cross section, right-click a Plane Geometry node under a Work Plane node or a 2D Geometry node and select Cross Section (
). Then enter the properties of the cross section using the following sections:
). By default, this computes the cross section of all 3D objects generated by preceding nodes in the geometry sequence. You can also select specific 3D objects to intersect with the work plane. You can also add a new 2D or 2D axisymmetric Component and add the Cross Section node there. In that case, you can select which Work Plane to use. For example, if you have a 3D geometry that is symmetric about an axis, you can add a work plane that contains the axis. In the axisymmetric 2D Component, you then get the cross section and can use a 2D axisymmetric component, which is computationally efficient compared to a full 3D component. A Cross Section node can also be useful to extract a planar surface for modeling a thin flat 3D structure using shell elements, for example. To add a cross section, right-click a Plane Geometry node under a Work Plane node or a 2D Geometry node and select Cross Section (). Then enter the properties of the cross section using the following sections:If you add the Cross Section node to a 2D or 2D axisymmetric geometry, first select the work plane to use for the cross section from the Work plane list.
From the Intersect list, choose All objects (the default) to intersect all 3D geometry objects with the work plane, or choose Selected objects to intersect only the geometry objects that you add to the Objects to intersect list that appears. Click the Active button to toggle between turning ON and OFF the Objects to intersect selections.
You can change the settings for the Repair tolerance list if you experience problems with the cross section operation. Geometric entities that have a distance less than the repair tolerance are merged.
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The default value in the Repair tolerance list is Automatic, which for 3D objects represented using the CAD kernel determines the repair tolerance internally. For 3D objects represented using the COMSOL kernel, and for 2D and 1D objects, Automatic means a relative repair tolerance of 10−6.
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Choose Relative to enter a value for the Relative repair tolerance field (the default is determined by the main Geometry node’s setting). This value is relative to the largest absolute value of the coordinates of all input objects.
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Choose Absolute to enter a value for the Absolute repair tolerance field (the default is determined by the main Geometry node’s setting; SI unit: m). This value uses the same unit as th geometry sequence’s length unit.
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When you build this feature, the relative and absolute repair tolerances are set to the values that are used (with a precision of two digits), which can be useful when you have set Repair tolerance to Automatic.
If you want to make the resulting entities contribute to a cumulative selection, select a cumulative selection from the Contribute to list (the default, None, gives no contribution), or click the New button to create a new cumulative selection (see Cumulative Selections).
Select the Resulting objects selection check box to create predefined selections (for all levels — objects, domains, boundaries, edges, and points — that are applicable) in subsequent nodes in the geometry sequence.
If you want to make the resulting entities contribute to a cumulative selection, select a cumulative selection from the Contribute to list (the default, None, gives no contribution), or click the New button to create a new cumulative selection (see Cumulative Selections).
Select the Resulting objects selection check box to create predefined selections (for all levels — objects, domains, boundaries, edges, and points — that are applicable) in subsequent nodes in the geometry sequence.
For a Cross Section node in a 2D component, you can also make all or one of the types of resulting entities (domains, boundaries, edges, and points) that the resulting objects consist of available as selections in all applicable selection lists (in physics and materials settings, for example). To do so, choose an option from the Show in physics (Show in 3D in a plane geometry under a work plane in a 3D component) list: All levels, Domain selection, Boundary selection, or Point selection. The default is Domain selection, which is suitable for use with materials and physics defined in domains. For use with a boundary condition, for example, choose Boundary selection. These selections do not appear as separate selection nodes in the model tree. Select Off to not make any selection available outside of the geometry sequence.