COMSOL 6.2 - Sweep

From the list, choose the level of the entities to sweep: , , or . Then select entities that you want to sweep in the window or use the window. Click the button to toggle between turning ON and OFF the selections. If the geometry sequence includes user-defined selections above the node, choose to select objects or entities, or choose one of the selection nodes from the list next to .

When sweeping boundaries, select the check box (active by default) to make the sweep operation create cross-sectional faces between the sweep sections. Such cross-sectional faces can be useful, for example, for a swept mesh where you want to specify the mesh distribution for each section of the sweep.

Select the check box (not active by default) to move the cross section entities to the start of the spine curve. This is supported for cross sections drawn in a Work Plane and it also matches the origin and z direction of the Work Plane’s coordinate system with the spine curve.

Select the edges you want to sweep along in the window. More than one edge can be selected, but the selected edges must form a nonclosed connected chain. The edges appear in the list. Click the button to toggle between turning ON and OFF the selection.

Select the check box to change the setting to manually control in which direction of the spine to sweep the cross section. These check boxes are only available when is not active.

The check box is selected by default. Clearing this check box means that transition zones are not added, which can give a better result in cases where the original edges already connect with a continuous tangent.

From the list, select one of the following options:

In the section select to modify the beginning of the spine curve to become perpendicular to the entities selected in the section. Change the (default 0.1) to modify how far along the spine curve the modification is allowed to propagate. Note that the parameter is dependent on the setting.

In the section select the check box to modify the end of the spine curve to become perpendicular to a selection of entities. Use this option to connect the end of the sweep with existing geometry with the addition of the option in the section if the entities do not match up perfectly. With the check box selected, click the button to toggle between turning ON and OFF the selections, then click to select entities in the Graphics window or use the Selection List. If is or , then the entities must span a plane. Change the (default 0.1) to modify how far along the spine curve the modification is allowed to propagate. Note that the parameter is dependent on the setting.

Select the check box to use the selected geometry objects for further geometry operations.

With the check box selected, select the check box to force the objects in the and lists to be included in the Form Union/Assembly operation. If the check box is not selected, these objects are automatically removed in the Form Union/Assembly operation if the list or list contains all entities in the objects of the selected dimension.

This section contains a number of properties that determine how the cross section is transformed when swept along the spine curve.

A curve parameter name can be defined in the field. Use this parameter in the expressions defining scale factor and twist angle. The parameter is increasing along the chain of edges to follow and is dependent on the setting. This is a local parameter used only for this operation.

Use the setting to control the twisting of the cross section along the sweep:

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Select (default) to let cross sections for nearby points on the spine curve have as small rotation as possible relative to each other. In other words, the cross sections follow a rotation-minimizing frame. This makes the edges in the sweep direction locally parallel to the spine curve. This option corresponds to the option in earlier versions.

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Select to let the orientation of the cross section be governed by a vector that is defined in the text fields , , and that contain expressions that can depend on the parameter. The cross section will follow the projection of this vector to the spine curve’s normal plane. For example, the default vector (0, 0, 1) means that a vector in the initial cross section that is horizontal (in the xy-plane) will stay horizontal in all cross sections.

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Select to let the orientation of the cross section be governed by the spine curve’s curvature vector (also called the normal vector), that is, the vector pointing toward the center of curvature. The local coordinate system formed by the spine curve’s tangent vector, the curvature vector, and the binormal vector is called the Frenet frame. It is not uncommon that a curvature vector varies in a wild way, which creates a bad result.

Select the check box to select a vertex in the entity to sweep and to match with a vertex at the end. The additional twisting and scaling varies linearly with the parameter. Use this setting together with the setting in the section to connect the sweep with existing geometry. Click the button (

) to swap the vertices in the two lists.

From the section, modify the following settings to add extra scaling and twisting to the cross section. These settings are applied after matching vertices, if active.

The field controls the size of the cross section, as a function of the parameter.

The field contains an additional rotation angle for the cross section, as a function of the parameter.

From the list, select (the default) to represent the swept object using splines, or , to represent the swept object using Bézier curves. With the option selected, the spine curve is represented by a sequence of many Bézier curves instead of a few spline curves. In addition to the cross section faces that are created between each pair of edges (if is selected), the operation creates cross section edges and vertices corresponding to the swept entities between each pair of adjacent Bézier curves.

The value in the field is a relative tolerance that controls the accuracy of the geometric representation of the swept object. The geometric representation is an approximation, which is necessary because it is not possible to exactly represent a swept object using NURBS (nonuniform rational basis splines). The default value is 10−4 (0.01%).

Internally, the software represents the swept object by B-spline curves and surfaces, which are computed to approximate the mathematical definition of the swept surface. The number of knot points in the splines increases automatically until the approximation satisfies the tolerance specified in the field or until it reaches the number of knots specified in the field (default value: 1000).

If more than one edge is selected in the list, the controls which edge is used to define the positive sweep direction. The is automatically set when the first edge is added to the list, so usually it does not have to be changed manually.

Select the 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. To 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), choose an option from the ( if in a geometry part) list: , , , , or . The default is , which is suitable for use with materials and physics defined in domains. For use with a boundary condition, for example, choose . These selections do not appear as separate selection nodes in the model tree. Select to not make any selection available outside of the geometry sequence. From the list, choose a color for highlighting the resulting objects selection. See Selection Colors.

If you want to make the resulting entities contribute to a cumulative selection, select a cumulative selection from the list (the default, , gives no contribution), or click the button to create a new cumulative selection (see Cumulative Selections).

If you have Named Selections that include entities on the input objects, select the (selected by default) check box to update the selections to corresponding entities on the output objects, when possible. Clear the check box to not propagate the selection to the resulting objects. This can be useful in combination with selecting the check box so that the selections refer only to the input objects.

From the list choose to make the resulting objects available only in the feature’s geometry sequence. The default option means that the resulting objects become construction geometry if all input objects are construction geometry. Choose to never output construction geometry objects. For more information, see Construction Geometry.