Using Work Planes
Creating 3D Geometries From 2D Work Planes and 3D Faces
In addition to creating 3D geometries directly using 3D geometric primitives, it is also possible to form 3D geometries based on 2D cross sections (2D geometries) created in work planes or faces in the existing 3D geometry. A work plane is a 2D plane oriented anywhere in the 3D space. Quick options make it easy to create a work plane that is, for example, parallel to any of the main Cartesian planes or to a face or edge in an existing 3D geometry. See Work Plane for more information about the settings.
There are several methods to create 3D solid objects from 2D sections or faces. In addition, you can use a 2D section as an “embedded” surface in the 3D geometry.
Drawing on a work plane works just as drawing in 2D. The 3D work plane adapts its size to the drawn geometry.
See the Learning Center resource Building Geometry Using COMSOL Multiphysics for examples and videos:
https://www.comsol.com/support/learning-center/article/Building-Geometry-Using-comsolmph-71841/192
See Electric Sensor: Application Library path COMSOL_Multiphysics/Electromagnetics/electric_sensor.
Use the instructions to practice building the geometry, which includes Work Plane, Rectangle, Ellipse, Union, Compose, Extrude, and Block features.
Uniting the Work Plane Objects
It is recommended to unite the work plane objects in 2D, if possible. The objects are united to one single object by default when leaving the Work Plane. Clear the checkbox Unite objects in the Settings window of the Work Plane to keep the separate objects when going to 3D. Keeping separate objects can be useful if modeling domains that will be sliding or moving relative to each other. See The Form Union/Assembly Node — Uniting the Geometry for more information. If you clear the Unite objects checkbox, use the Union operation in the work plane to unite as much of the objects as possible.
It is also possible to add a Form Union/Assembly node from the Booleans and Partitions () menu. The Form Union/Assembly node has the same effect at the Unite objects checkbox, but also enables the possibility to add virtual operations to remove short edges, small faces, and similar already in the work plane.
Adding Virtual Operations in the Work Plane
Remove small details from the work plane geometry and prepare it for efficient meshing and analysis by adding operations from the Virtual Operations () menu. See Table 7-14 for a list of available operations. It usually simplifies the workflow by removing unnecessary details early in the process. If there is no Form Union/Assembly node in the sequence when the virtual operation is added, it will be added automatically. The state of the Unite objects checkbox of the work plane determines which node is added; a Form Union node (checkbox selected) or a Form Assembly node (checkbox cleared).
Drawing on a 2D Work Plane in 3D
When using a Work Plane () node to define 2D objects in 3D (for example, to extrude into a 3D object), the 3D projection settings enable you to draw on the work plane in 3D. These instructions provide an example. When the View work plane geometry in 3D checkbox is selected in the Settings window for the Plane Geometry node () under the Work Plane node, two additional buttons are available in the Graphics window — the Align with Work Plane button () and the Work Plane Clipping button (). The Sketch and Work Plane toolbars are also available for use. The upside of the work plane (defined by the plane’s normal axis) look blue; otherwise, it looks yellow (when using the standard color themes). Those colors help you understand which side of the plane that you are looking at.
Some computer graphic cards cannot run the work plane rendering. In these cases, the work plane is rendered as a blue plane. It is possible to go to the 3D work plane but not to draw on the plane.
1
Add a 3D Component and either leave it empty or add a geometry (for example, import a CAD part or a geometry file).
2
In the Geometry toolbar, click Work Plane (or right-click Geometry 1 and select Work Plane.
3
Under Work Plane click the Plane Geometry node, click the Go to Plane Geometry () button in the Settings window, or click the Select Work Plane () menu in the Geometry toolbar and select an existing work plane.
4
Under Visualization, select the View work plane geometry in 3D checkbox, as shown in Figure 7-12.
Figure 7-12: The Graphics window displaying the Work Plane Geometry when the View work plane geometry in 3D checkbox is selected.
5
The geometry displays in the Graphics window. See Figure 7-11 for an example.
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Click the Align with Work Plane button () to rotate and move the camera to see the work plane from the top down.
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Click to toggle the Work Plane Clipping button () on and off. When on, use it to cut away all geometries above the work plane and make it easier to draw when objects are overlapping within the work plane. The clipping is not done when looking at the work plane from the side.