Tabular Material Data  —  When importing tabular data for a material property, the first data point is used to complete the material definition.

NX Color Attributes  —  NX color attributes can be imported using the 'Color' key in the list of attribute or the named selection keys. Once the attribute or named selection import is enabled in the WB2 geometry properties window, append the 'Color' key in the list of keys, separated by semicolons, to import the NX color attributes. Note that, beginning with Release 14.5, the option for 'NX Color Processing' is not supported and is removed from the CAD configuration.

Load Options  —  Load options for a part can be specified during the import. The Plug-in will first attempt to load the options from the options file specified using the UG_LOAD_OPTIONS environment variable. If it fails, an attempt to load the load_options.def file from the part directory is made. If both the attempts fail, a third attempt is made to load the options from %HOME%\load_options.def, where HOME is an environment variable pointing to the user's home folder. See the NX documentation for more information on the usage of load options.

It is recommended that all models for import have only parts that use the same unit system as the assembly of which they are included. This can be achieved by using the ug_convert_part command to convert all parts in an assembly in the same unit. To do this, launch the NX command prompt from the programs menu. For NX continuous release series the command prompt can be found in Programs > Siemens > Tool – NX Command Prompt. Type ‘cd<Directory>’to change the directory containing the assembly. Run the command 'ug_convert_part -mm -d -s -y' or 'ug_convert_part -in -d -s -y', without the quotes to change the unit to millimeter or inch, respectively. See the NX documentation on the ug_convert_part command for more information. Assemblies that are imported using parts with units systems that differ from that of the assembly will have those parts scaled to generate a consistent unit system for all components.

Using Multiple Versions of NX  —  If you have multiple versions of NX installed, you must make sure that the UGII_BASE_DIR and UGII_ROOT_DIR environment variables point to the correct version of NX when running the Ansys Mechanical application in Reader mode.

The NX reader will use the version of NX set by these variables when processing the attach or updates. Parts files are saved in the format designated by the above two variables.

Maintaining Associativity of Persistent IDs  —  Object associativity is of particular importance if you update/refresh a geometry with applied loads and supports. The Ansys NX geometry interface uses the User Defined Objects (UDO) to store persistent IDs to maintain the associativity of the geometry between NX and the Ansys Mechanical application. The part file must be saved after import to store this data in the NX model. This can be done by saving the file in NX after an attach via an NX Plug-in session, or with the use of the 'Reader Mode Saves Updated File 'option within the Ansys application when using the Reader mode for import. The 'Reader Mode Saves Updated File' option can be found under the 'Advanced Geometry Options' group on the Ansys Workbench Project page. The part file will be saved at the end of an import process using the same file name in the same directory. The current part file will be backed up by changing the extension of the file to bak before saving the part. Make sure that the file is not set to read-only.

Parametric update also requires the UDOs to have been saved in the NX model. It is important to note that if you make parametric changes those too will get saved and the model will be modified from the original version.

If you do not save the parts files, during an update after the initial attach, the loads and supports could disappear or be applied to the wrong entities.

Facet Smoothness Control  —  The geometry faceting obtained by the Ansys NX geometry interface is view-dependent. That means the facet smoothness of the imported geometry depends on how the object is displayed on the screen. Although the default settings are generally acceptable for most of the cases, these may not be adequate for a geometry needing smoother facets. The facet smoothness in such cases can be controlled by the ANS_UG_FACET_AFFINITY environment variable.

The variable can be set to any floating point number from 1e-8 to 1e+8. The higher the value is, the finer the facet will be and the longer it will take to import the geometry. If the variable is absent or outside the acceptable range, 1.0 will be assumed as the default value for it.

Note that this environment variable may get removed entirely or replaced by a more user friendly variation in the future release.

Imported Body Size  —  All NX bodies must be within a 1000 x 1000 x 1000 meter cube, centered about the origin of the absolute coordinate system.

Initial Launch  —   After installation of Ansys Workbench, importing an NX model using the Reader mode requires the CAD be launched one time. Otherwise, the first attempt to import will fail, but subsequent attempts will work normally.

Large Number of Named Selections  —  In an assembly or a part with a large number of named selections, close to about a thousand, NX might close unexpectedly when you try to add more than 10 named selections at a time in the list. To avoid the problem, add few named selections at a time, close the named selection manager and save the part. This problem does not affect a list of named selections less than about a thousand, and the workaround is not needed for such cases.

Length Unit  —  The Ansys Mechanical application automatically sets the length unit in the part or assembly to match the unit saved in the NX file. No adjustment of length unit is necessary or possible.

Material Property Values  —  There are known irregularities in material property values passed from NX to Ansys Workbench. Validate all material data prior to solving.

Missing BSpline Geometries in DesignModeler  —  Some solids, surfaces and lines containing Bspline geometries may not import correctly into the DesignModeler application, but should import correctly in the Ansys Mechanical application. Since these Bspline geometries do not conform to the Parasolid standard, they do not import correctly into the DesignModeler application. Newer geometries containing Parasolid-friendly Bsplines can be imported into the DesignModeler application without any problem.

Mixed Unit Support  —  It is recommended that all parts and sub-assemblies in a model should be in the same unit system. Models with mixed units will be imported into Ansys applications with all parts scaled to the assembly unit system. A warning will be issued during the import indicating the mixed units of the model.

Multibody Parts  —  For multibody parts, the bodies are grouped together and placed under part node in the Ansys Mechanical application. If the multibody part is also multi-dimensional (that is, contains both surface and solid bodies), this may cause a meshing problem. Bodies with different dimensions in the same part cannot be meshed in Ansys Mechanical. An assembly, instead of a multi-dimensional multibody part, can solve the problem in such cases.

Named Selection Delete Problem with Wave Linked Features  —  Features containing wave linked geometries may not show the correct number of named selections after some of the named selections are deleted. For example, if an "Extracted Face" feature is created from a solid body and a named selection is created containing both the geometries, deleting that named selection may not delete it from the list. To fix the problem, close the Named Selection Manager and update the geometry using Edit> Feature> Playback or Tools> Update> Update for external change. The named selection manager should reflect the correct number of named selections after the update.

NX model import into Fluent on Linux may time out and fail  —   Work around this issue by modifying the UGTserver.sh script located under the aisol/CADIntegration/linx64/ directory of the Ansys installation, inserting the following after the first line:

export UGII_BASE_DIR=your/nx/install/path/here
export SPLM_LICENSE_SERVER=your/license/server/here

Parameter Update Fails Instead of Displaying a Warning Message  —  The NX plug-in performs an undo operation when it encounters an error or a warning during a parametric update. The undo operation allows you to change the parameter back to a correct value. Fix the error or the warning message in NX before performing a parametric update on such a part. Alternatively, set an environment variable called UGII_UPDATE_FAIL_OPTION with a value “ACCEPT” or “ACCEPT_ALL” without the quotes and unset the variable once the parameter update is done. This will allow the import to work even if there is a warning or a failure.

Promoted and WAVE Linked Instances  —  If the instanced bodies are promoted, they will be treated as independent bodies. The algorithm to avoid duplicate copies of instanced bodies will skip promoted bodies. Thus, if there are assembly-level operations on the promoted instances, the modified bodies from those operations will get imported correctly. The same is true for WAVE linked instances as well.

Surface Body with Thickness  —  If your NX surface body model has a thickness defined and it does not get transferred to the Ansys Mechanical application, this could mean that you do not have an NX Scenario (Structural) license. Moreover, only the mid-surfaces created using the offset command can have thickness property and are imported correctly. Mid-surfaces created using face pair or user defined methods cannot have a thickness and cannot be imported. In addition to that, any thickness assigned on the surfaces inside the Advanced Simulation application cannot be imported in Ansys either.

Unique Parameters Name  —  When you transfer NX expressions/parameters into the Ansys Mechanical application, make sure that all feature parameter names are unique within a part and all non-feature parameter names are unique within an assembly. The non-feature parameters could be from one or more components of the assembly.

Library Conflict  —  The following limitation is specific to the Ansys 2024 R2 Associative Geometry Interface to NX. There is a known library conflict with earlier releases of this Plug-In, which causes the 2024 R2 Plug-In to fail to load into NX when a previous release of the Plug-In is loaded into NX.

Use the following procedure to enable theese versions to be loaded side-by-side into NX.

Parameters Placement – When a parameter's units are defined in the "Tools > Expressions" dialog in the formula field it will be processed as a dependent variable and placed in the Output list when promoted.

Simple version requirement– Siemens does not support multiple versions of the NX continuous release product line simultaneously installed on a single system. Such configurations may cause the Associative Geometry interface to fail.

See the NX Errors Related to CAD Integration section in CAD Integration Troubleshooting for detailed information.