Under a Geometry node (
) you define and create the geometry sequence for the model component. The
Geometry node also contains some general settings for the geometry such as the length unit.
To add a new Component, which includes a Geometry node, right-click the root node of the Model Builder, and select
Add Component (or use the
Model Wizard to create a new sequence as described in
Creating a New Model). A
Component node is added to the
Model Builder containing a
Geometry 1 (if it is the first Component) feature node with the start of a geometry sequence containing only a
Form Union node (see
Figure 7-2 for an example).
To open the Settings window for a geometry, click the
Geometry node in the Model Builder and adjust the following settings sections.
Select the Scale values when changing units check box to scale the values for the geometric dimensions so that the geometric objects keep their physical size. The default setting is to not scale the values when changing units; the program then interprets the values for the geometric dimensions using the new units for length and angle. The values themselves do not change.
From the Length unit list select the length unit to use in fields for lengths and for visualization of the geometry. You can override the unit using the unit syntax to specify the length unit (for example,
13[mm]). When solving the model, all lengths are converted to the base unit for length. If you change the unit, COMSOL Multiphysics converts all pure numeric values in fields for lengths to the new unit, if you have selected the
Scale values when changing units check box (see above).
From the Angular unit list choose to use radians or degrees as the angular unit to use in fields for angles. You can override the unit by entering, for example,
0.3[rad]. The program assumes that numeric inputs and outputs of trigonometric functions are in radians. If you change the unit, all pure numeric values in fields for angles are converted to the new unit, if you have selected the
Scale values when changing units check box (see above).
Use the Use constraints and dimensions list to enable or disable the use of geometric constraints and dimensions. The default for this setting is determined by a preference settings on the
Geometry>2D Constraints and Dimensions page in the
Preferences dialog box: Select or clear the
Use in new models check box. This preference setting is On by default. In the
Preferences dialog box, you can also specify the
Maximum number of entities in the constraints and dimensions solver (the default value is 10,000 geometric entities). You can use this limit to prevent lengthy computations for very complex 2D geometries when using the constraints and dimensions solver.
If you have selected On, the
Constraint and dimension features to build list determines what constraint and dimension features to include when building the geometry:
This list is only visible if you have a license for the CAD Import Module. The Geometry representation list controls which kernel (geometric modeler) that COMSOL uses to represent and operate on the geometry objects: the CAD Import Module’s kernel (Parasolid) or COMSOL’s own kernel.
When you change the Geometry representation setting, all nodes that support the CAD kernel are marked as edited with an asterisk (*) in the upper-right corner of the node’s icon. To rebuild the geometry using the new kernel, click the
Build All button (
). To avoid re-solving an already solved model, you can click the
Update Solution button (
) in the
Study toolbar to map the solutions from the geometry represented by the CAD kernel to the new geometry represented by the COMSOL kernel.
If your license includes the Design Module and the geometry representation is set to use the CAD kernel, you can select the Design Module Boolean operations check box in a 3D
Geometry node’s
Settings window to use the 3D Boolean operations available with the Parasolid kernel. Those operations might perform better in some cases. When you open an existing model, you normally use the Boolean operations used in the model. To always get the possibility to use the Design Module Boolean operations, change the preference setting
Geometry>Geometry representation>3D Design Module Boolean operations to
Use in new geometries.
This is the default value that is used when you add a feature that has a Repair tolerance list (for example, Boolean operations and conversions):
The Build new operations automatically check box controls if certain geometry operations will be built automatically when you add them, provided that you have preselected a sufficient number of entities or object. The default value is controlled by the preference setting
Geometry>Build new operations automatically>In new geometries. It is selected by default to always rebuild the geometry when using the factory settings. Clear it to prevent any geometry operations from being built automatically.
The Build automatically when leaving geometry check box controls if the geometry sequence is automatically rebuilt when clicking on a node in the model tree outside the geometry sequence. The default value is controlled by the preference setting
Geometry>Automatic rebuild when leaving geometry>In new geometries. It is selected by default to always rebuild the geometry when using the factory settings. Clear it to prevent any automatic rebuilding of the geometry.