Projection
Use the Projection feature to compute the projection of 3D objects and entities to a work plane. This can be useful when you need to reference existing 3D objects in the 2D drawing on the work plane. You can also add a new 2D or 2D axisymmetric component and add the Projection node there. In that case you can select the work plane to use for the projection from the 3D component’s geometry sequence, but first make sure that in the 3D component’s Geometry node the Geometry representation is set to the CAD kernel.
To add a projection to a Work Plane node’s Plane Geometry sequence, from the Plane Geometry toolbar select Projection (), or right-click a Plane Geometry node under a Work Plane node and select Projection (). Enter the properties of the projection using the following sections:
Projection
From the Project list, choose All objects (the default) to project all 3D geometry objects to the work plane, or choose Selected objects, Selected domains, Selected boundaries, Selected edges, or Selected vertices to project only the objects or entities that you add to the Entities to project list that appears. For Selected Objects, choose All objects to select all objects or choose All nonconstruction objects to automatically select all objects that have not been marked as Construction Geometry. If the geometry sequence includes user-defined selections above the Work Plane node, choose Manual to select objects or entities, or choose one of the selection nodes from the list next to Entities to project.
Click the Activate Selection button to toggle between turning ON and OFF the Entities to project selections.
When projecting objects, domains, and boundaries you can select the Projection type to project the Outline (default) of the selected objects and entities, or to project the Edges and vertices only, or the Outline, edges, and vertices.
Projecting the outline for surface and solid objects results in the edges that form the boundary of the shadow of the object’s faces. In this case the edges are projected only if they coincide with the outline. If you project the outline of a mixed object that contains isolated edges and vertices, only the outline of the faces is generated, the isolated edges and vertices are not projected.
For point and curve objects, projecting the outline is the same as projecting the edges and vertices.
You can change the settings for the Repair tolerance list if you experience problems with the projection 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 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 the geometry sequence’s length unit.
When you build this feature, the relative and absolute repair tolerances are set to the values that are used for the last projected object (with a precision of two digits). This is useful to find out the tolerance used for the last projected object. After the feature is built, you can set the Repair tolerance to either Relative or Absolute, then check the values displayed in the Relative repair tolerance or Absolute repair tolerance fields.
Selections of Resulting Entities
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 in the COMSOL Multiphysics Reference Manual).
Select the Resulting objects selection checkbox to create predefined selections (for all levels — objects, boundaries, and points — that are applicable) in subsequent nodes in the plane geometry sequence. To also make all or one of the types of resulting entities (objects, boundaries, and points) available as selections in applicable selection lists in the main Geometry node’s geometry sequence, choose an option from the Show in 3D list: All levels, Object selection (default), Boundary selection, or Point 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 plane geometry sequence.
Assigned Attributes
From the Construction geometry list choose On to make the resulting objects available only in the feature’s geometry sequence. The default option Inherit from input means that the resulting objects become construction geometry if all input objects are construction geometry. Choose Off to never output construction geometry objects. For more information see Construction Geometry in the COMSOL Multiphysics Reference Manual.