Supplier Siemens NX export settings into Rhino

Hello, a supplier ship designer has made a detailed 3d model of the ship with many parts and systems in Siemens NX and also Cadmatic.
When they send the STEP file exported from Siemens NX (~1Gb) and I open in Rhino 7, there is only 1 layer which makes it unworkable.

I would like to see more layers, groups, blocks and the same colors.
Does anyone knows how to achieve this?

Hi Ram - this may be controlled at least in part by settings on the exporter, I don’t know. It may also be possible to export multiple step files that can be assembled in a Rhino ‘Worksession’. Do you see one top level block instance when you open the large file?


Thanks. Worksession looks good, I was not using it. There is only one layer (Layer 01), and only a few blocks, most is surfaces.
We tried exporting different files by system, although is safer to export the whole model at once to not lose any items.
Yes I’m aware the issue is mostly on there side with the export settings, it’s not straightforward apparently.


It will be entered as a block when you have checked the assembly and the layers and groups have been applied correctly.
You can use Ap242_AP214 format

Export STEP File dialog box

The options for exporting to STEP are almost identical in the following dialog boxes:

NX dialog box:

  • File tab→Export→STEP→Export to STEP Options dialog box

NX Data Exchange dialog boxes:

  • Siemens NX→Translators→Step AP203→Step203 Export→ Data Exchange dialog box
  • Siemens NX→Translators→Step AP214→Step214 Export→ NX Data Exchange dialog box

Some options have different names in the NX and NX Data Exchange dialog boxes. Some options are available only in a particular dialog box.

NX STEP options NX Data Exchange STEP options Description
Files tab
Export From Files to Export Specifies the part to export. You can export data from the displayed part or an existing part.

Part File

Appears when Export From is set to Existing Part. Sets the path of the part file that you want to export.|
|Output File Destination||Available in Teamcenter Integration for NX.

Sets the destination for the file to export:

  • Filesystem
  • Teamcenter|
    |Export to|Files to Create|STEP File

Sets the path of the STEP file to be saved.|
|Application Protocol||Specifies the STEP format to which the translator exports part file data from NX.


If you select AP242 format, by default the translator exports the NX data to STEP 242 Edition 2. To export NX data to AP242 Edition 1, you must set APPLICATION_PROTOCOL = AP242 in the settings file.|
|Settings File|Settings File|Specifies the STEP settings file that the translator uses to export part file data from the NX to the STEP format.|
|Load From||Sets the path of the settings file that you want to use to export data from NX to the STEP format.|
|Save Settings to File|N/A|Sets the file name and the path to be used to save the customized settings file.|
|Save|File→Save As|Lets you create a new settings file or replace the existing settings file.|
|Data to Export tab|
|Model Data|Object types

(Only the Select object types option is available)|Lets you select the object types of the data to export, such as curves, solids, surfaces, kinematics (STEP AP242 only), and so on. By default, the Solid object type is selected.

The Export option appears when Export from is set to Displayed Part on the Input and Output page. Exports the part data from the selected part file.

Entire Part

Exports all the objects from the selected part file.

Selected objects

Lets you select objects of different units from an assembly, such as inches and millimeter.

Select object types

Lets you set the object types data to export, for example, curves, solids, surfaces, convergent bodies, facet bodies, and so on. By default, the translator selects the Solids object type.


The Tessellation object type is specific to the STEP AP242 format and the Product Data object type is specific to the AP203 and AP214 STEP formats.

The Convergent Bodies and Facet Bodies options are specific to AP242|
|Export Precise Bodies as|N/A|Precise

Exports classic NX bodies as precise geometry.


Exports classic NX bodies as tessellated geometry.


  • This option is specific to AP242, and is available when you select the Solid or Surfaces option .
  • When set to Tessellated, the tessellation parameters are used as Chordal tolerance = 0.005 inches and Angular tolerance = 15 degrees.|
    |Export Convergent Bodies as||Specifies the how the convergent bodies with precise faces are exported to STEP AP242 files. You can export as Split Precise and Tessellated or Tessellated geometry.|
    |Include and Exclude|Layers to Export|Lets you limit the data export by enabling or disabling the layers. Enter layer numbers or layers ranges separated by commas.


1, 5, 88-109, 201, 206-210

By default, the STEP translator exports layers 1-256.|
|Advanced tab|
|Long Name

Short Name|Use Long Name

(Only the Long Name option is available)|Long Name

Enables long name extensions for STEP-specific information.

Short Name

Enables short name extensions for STEP-specific information. If the sending system does not support the Long Name extensions, select the Short Name option.

By default, the STEP translator exports long names for the STEP entity types.|
|Color and Layers|Include Color and Layers|Applies to STEP AP203 only. Exports the colors and layers information to the STEP AP203 file.


Colors and layers are part of STEP AP214 standards, and are included in the export by default.|
|Export User Defined Attributes||Applies to STEP AP242 only.

Exports the user-defined attributes.|
|Export System Attributes||Applies to STEP AP242 only.

Exports the system attributes, such as density, mass, and so on.|
|Validation Properties|Include Validation Properties|* For STEP AP203 and STEP AP214, exports validation properties to the STEP format. The validation properties contain information corresponding to volume, surface area, and centroid.

  • For STEP AP242, exports validation properties to the STEP format. The validation properties contain information corresponding to:
    • Geometric—Volume, surface area, and centroid
    • Cloud of Points—Point cloud data for validation
    • PMI—Semantic and graphic properties of PMI
    • Assembly—Number of children and notional solid centroids|
      |External References|External References|Export Assembly As External Reference

Enables the export of the assembly as an external reference.

Export Structure As

Appears when Export Assembly As External Reference is selected.

The STEP translator supports two external reference formats.

  • The BASIC format exports the NX assembly structure information and first level NX subassembly (or parts) in that assembly as separate files.
  • The NESTED format divides the complex NX assembly structure into several sub-assemblies, which it exports as individual part files.|
    |B-spline Tolerance|B-spline Approximation Tolerance|Sets the accuracy used during export to approximate NX objects into STEP.

When the translator must approximate a face into a B-spline surface or an edge into a B-spline curve, the B-spline approximation tolerance value is the upper bound on the distance between the B-spline approximated representation of the face or edge and the corresponding original face or edge.

By default, the STEP translator uses 0.0254 mm as the B-spline approximation tolerance.

If you use a value that is one order of magnitude smaller than the machining tolerance, the translator reduces the exported file size and still maintains the required accuracy.


The unit of the value displayed or entered is based on the units of the current work part. The translator writes the value to the .def settings file in millimeters and converts the value to an appropriate work part unit when read by the interface.|
|N/A|Assembly Options|Use Load Options.def

Uses the load_options.def file to obtain the assembly load options.


Lets you specify the load options that you want the translator to override in the load_options.def file.

  • Abort on Component Load Failure: Stops the loading of the assembly file if any one component fails to load.
  • Allow Substitutions: Lets you replace component parts with another parts.
  • Version: Specifies the version of the component. This information is useful when multiple Part Name Versions are defined in NX customer defaults. The Latest option opens the latest version and the Exact option opens the version that was loaded when the assembly was last saved.
  • Location: Specifies the location from which to load components.

Search Directories

Loads the first component found in the hierarchal list of directories.|
|Header Information|Header Information|Lets you modify information found in the Global section and the Start section of the STEP file. This option is useful when you want to provide information about the person and company sending the file, the type of parts it contains, and so on.

The header information consists of the following categories which correspond to their respective keywords in the settings file. You can enter up to 48 characters for each category.


Sets the name of the person who generates the STEP file.


Sets the name of the company from which the STEP file originates.


Sets the name of the person who authorized the part for release.


Sets the name for a part that is referenced by the sender.|


Thank you!

1 Like

Making progress now. The new file has blocks and sub blocks but it’s still in only one layer.
I have seen in this forum before an old post with a script to convert ‘blocks to layers’.

I could do it manually, though it’s a large file and we expect new updates inn the future.

Would anyone know of an updated ‘blocks to layers’ script, or work around?
Thank you.

ExplodeBlocksToLayersV6.rhp (15.5 KB)
Hi Ram - this is the ExplodeBlocksToLayers plug-in - I do not know how it will do with a massive file, you’ll just have to try it. Check the command line option for how layers are assigned - there are two possibilities.

Unblock the rhp file in Windows Explorer and then drag and drop it onto Rhino.



Hi Pascal, thank you very much for the script. It works well and it solves the issue! Much appreciated.
Best regards