The LiveLink for Inventor feature, available from the LiveLink menu in the Home toolbar, synchronizes the geometry between Autodesk® Inventor® and COMSOL Multiphysics®.

For geometry synchronization to take place both COMSOL Multiphysics and Autodesk® Inventor® need to be running, and the CAD file needs to be open in the CAD software. When this is not possible, Offline Synchronization is available so that you can, from the CAD software, save synchronization files, which you can load into the LiveLink node.

During synchronization the LiveLink™ interface initiates a rebuild of the CAD geometry in Inventor® based on the parameter values set in the COMSOL Multiphysics® model, then associatively transfers the rebuilt geometry to the model to ensure that physics and other model settings are retained on the geometric entities where they were originally defined.

In the geometry sequence of the model the LiveLink node signifies a geometry synchronized from the CAD software, and in many aspects it is just like any other geometry operation. It can be combined with other operations that may appear both before and after the LiveLink node in the sequence. The exception to this is when modeling in the embedded COMSOL environment inside the Inventor® user interface, where the Geometry from Inventor® node is the only allowed geometry operation, and it is automatically added to the geometry sequence as soon as a new model is created.

Synchronized geometry objects are represented using the Parasolid® geometry kernel inside COMSOL Multiphysics. Thus, you can apply all the tools and features for defeaturing and geometry modification as included with this LiveLink™ product.

To specify which CAD document to synchronize use the Synchronize with list. Select Active document to synchronize the open and active CAD document in Inventor®. For the initial synchronization after adding a LiveLink™ node, Active document is the only available setting. For subsequent synchronizations the Specified document option becomes selected instead. Using this setting the CAD document specified after Document will be synchronized provided that it is open in Inventor®. To synchronize a new CAD document switch to the Active document setting. The name of the CAD document is automatically determined during synchronization with the Active document setting.

The LiveLink interface also determines the Table record and the View, Position, and Model state representations used in the synchronized Inventor® document when Synchronize with is set to Active document. To make sure that the CAD document will be synchronized in the same state during subsequent synchronizations, the Specified document alternative can be used. With this option the interface automatically activates the last synchronized table record and representation. To be able to synchronize the CAD document in a different state, first make the switch to the desired table record or representation in Inventor®, then from the Synchronize with list select Active document.

For information on how to use tables to manages configurations for parts and assemblies, and how to use the different representations see the Inventor® documentation.

You can also select to Synchronize material data together with the geometry. With this option the interface imports the material properties defined in the synchronized part or assembly components, and the software creates corresponding Material nodes in the component. The input selection in the generated Material nodes is set to the material selections that are also created during synchronization; see Selections, for more information.

To initiate a synchronization click the Synchronize button. This sends parameter value pairs to Inventor®, then retrieves the regenerated geometry objects. Synchronization can also be triggered by clicking a build button when there are changed settings in the LiveLink node, or there are changed parameter values. Synchronization is automatic when running an optimization study or a parametric sweep.

By default, only the objects that are visible in the Inventor® user interface are synchronized. For CAD assemblies you can also select the parts to synchronize without changing their visibility, see how in the section The COMSOL Component Selection Window.

Select the Offline synchronization checkbox to enable the Offline Synchronization section where you can load synchronization files that you have prepared in advance using the LiveLink tools in Inventor®. Such offline synchronization files can contain the geometry, selections and parameters for several synchronizations, including parameter sweeps.

To load a synchronization file, from the Offline Synchronization toolbar, click Receive Synchronization File (). Browse to the file and click open to load the geometry, parameters and selections from the file. Synchronization files may contain one or several synchronizations, including synchronizations generated in response to a requested parameter sweep.

If the loaded synchronization file contains a parametric sweep the number of parameter tuples in the file is displayed under Receive. After the file is loaded, you can go to the Study node that contains the parametric sweep for which the synchronization was requested, and click Compute to run the parametric sweep.

In case a loaded synchronization file contains several synchronizations you can see the number of synchronizations left in the file under Receive. To load the next synchronization from the file click Load Next Synchronization ().

To request a synchronization click Request Synchronization (). You can, for example, under Global Definitions > Parameters, change the value of a parameter that is synchronized (see Parameters), and then generate a synchronization request. The response you will generate in Inventor® will contain the updated geometry according to the parameter value in the request. To save another request to the previously saved request file click Append to Request File (). To generate a request for a parametric sweep select one of the available sweeps from the Parametric sweep to request list, and then click Request Synchronization to save the request.

Parameters that take part in the synchronization are specified in the Parameters in CAD Package section. Based on the transferred parameter and value pairs in the Controllable parameters table, the CAD model is automatically rebuilt in Inventor® and transferred back to COMSOL Multiphysics®. This way you can control dimensions of the CAD design, for both parts and assemblies, and their components.

Together with the updated geometry, updated values of the parameters listed in the Read-only parameters table are also transferred from the CAD software. Read-only parameters are defined by a formula in Inventor®, and therefore not possible to control without breaking the CAD design. However these parameters can be used to set up the simulation.

Clicking Synchronize also retrieves parameters that not yet appear in the tables under the Parameter in CAD Package section but have been selected to be linked to COMSOL® from the Inventor® file. As part of this process a corresponding global parameter is automatically generated in the model.

In both the Controllable parameters and Read-only parameters tables, the CAD name column holds the names of parameters in the CAD file, whereas the COMSOL name and COMSOL value columns contain the name and value, respectively, of corresponding global parameters in the model, defined under Global Definitions > Parameters in the model tree. Global parameters can be controlled by the parametric solver to perform parametric sweeps. During synchronization of controllable parameters COMSOL evaluates the corresponding global parameters and sends the resulting value to Inventor®. Click the symbol in the Sync column to turn on or off the synchronization of a parameter.

Unless a unit is specified the updated parameters are assumed to have units as defined in the Inventor® file.

You can type in parameters in the tables, or use the COMSOL Parameter Selection window in Inventor® to link parameters from the Inventor® file, for details see the section The COMSOL Parameter Selection Window. Linked parameters can then be retrieved to the table, and global parameters are automatically generated for them. This process is automatic when modeling with COMSOL inside Inventor®.

To retrieve the linked parameters from the Inventor® file to the LiveLink node, and to generate corresponding global parameters in the model do one of the following:

Parameter names in the CAD name column appear just as in the Inventor® file, for example d1. When the parameter refers to components of the synchronized assembly the syntax also includes the name of the component, for example d1.part1.ipt. This makes it possible to control parameters from components of an assembly.

In the Length unit list, select From COMSOL to scale the transferred objects to the length unit of the geometry in the current model. Select From CAD document to change the geometry’s length unit to the unit in the CAD software.

One way to prevent synchronization of construction surfaces and curves is to hide them in the Inventor® user interface. An alternative is to set the LiveLink interface to omit them from the synchronization. Only the types of objects that are selected from the Solids and Surfaces checkboxes are transferred during a synchronization. Performance can be improved for very large geometries that contain more than one type of objects, by turning off the synchronization of types of objects that are not necessary for the simulation.

The Absolute import tolerance is a length measured in the geometry’s unit after synchronization. This tolerance is used by some of the simplification and repair operations as detailed in this section. During the import of objects transferred from Inventor®, the repair operations are performed in the order of the corresponding settings (starting from the top) in the user interface.

If the Remove redundant edges and vertices checkbox is selected, edges and vertices that are considered redundant, such as the edges of an imprint on a face, are removed from the imported geometry.

Imported geometric objects can sometimes contain geometric and topological errors, including missing edges and vertices, and entities with invalid sense and invalid tolerance. Errors such as these can be fixed during the import by choosing one of the available options from the Fix errors list:

Select the option Simplify curves and surfaces to simplify, within the Absolute import tolerance, the underlying curve and surface manifolds of the imported geometric entities. Importing objects with this option may improve both the performance and reliability of geometric operations on some imported geometry, for example it may help in some cases when Boolean operations on the imported objects fail. Simplification means that the manifolds are converted where possible to analytical form: linear, circular, and elliptical curves; and planar, spherical, cylindrical, conical, and toroidal surfaces. Manifolds that are converted are B-spline curves and surfaces, or certain surfaces generated by operations such as sweeping, revolving, and filleting.

Select the Delete small details checkbox to remove geometric details smaller than the Absolute import tolerance. Details that can be deleted include short edges, sliver faces, small faces, and spikes.

Select (default) the Check imported objects for errors checkbox to check the validity of the imported objects as the last stage of the import. Warning nodes appear with details about the detected problems, if any. Use the Zoom to Selection button next to the Entities list in a warning node to locate the problematic edges or faces. For information on geometry problems that may occur see the Check feature.

The associativity between the geometry transferred to COMSOL Multiphysics and the geometry in Inventor® is preserved as long as the topology of the geometry does not change. If the topology changes, for example if new faces are introduced or faces are removed, the interface tries to preserve associativity for the portions of the geometry that remain unchanged.

To make sure that the geometry stays associative to the geometry in the CAD program even after saving and reopening your work in COMSOL Multiphysics and Inventor® it is recommended to save the Inventor® file in the state corresponding to the latest synchronization. To make sure that the geometry stays associative during several offline synchronizations it is recommended that you load the synchronization files in the order that you have saved them in the CAD software, and that you define selections, see The COMSOL Selections Window.

The LiveLink™ interface automatically synchronizes selections for materials from the Inventor® document. The selections get their names from the names of materials assigned to objects or other geometric entities on the synchronized CAD geometry, and they appear in Selections tables according to the entity level they are defined on. Click on an entry in a table to see the included entities highlighted in the Graphics window. When setting up a simulation you can use selections for example for assigning materials on the finalized geometry. You can read about how to turn off the automatic generation of selections for materials in the section The COMSOL Selections Window.

In addition to automatically synchronizing selections for materials you can also define custom selections on the CAD design in the Inventor® user interface and synchronize those with the COMSOL model, for details see the section The COMSOL Selections Window.

User defined selections are listed alongside material selections in the Selections tables, according to the entity level they are defined on. Click on a selection to see it highlighted on the geometry in the Graphics window.

Select the Construction geometry checkbox to make the resulting objects available only in the feature’s geometry sequence. For more information see Construction Geometry in the COMSOL Multiphysics Reference Manual.