NX Handling of invisible layers when performing a NX to STEP translation

Exporting a NX part file to STEP AP203 or AP214, when viewing the STEP data after import to a receiving system, allthough the geometry quality is good, the result does not look entirely as the part looked in NX. There are additional solid body shapes, which give the impression that some feature operations, like Trim or Delete Face in NX have not been included in the translation. 

From where does this extra geometry come?

Solution

As a background to the geometry referred to in this FAQ, to understand the observations in the symptoms given above, the NX part file being translated to STEP contains multiple solid bodies. All but one is hidden using invisible layers.

The NX to STEP203 and STEP214 translators translate layers and their status as they are in the NX part file you are translating, i.e. objects reside on the layer that they reside on in NX, visible layers with objects remain visible and invisible layers with objects remain invisible.

However, when you come to the receiving system for your NX STEP file it is important to keep in mind that far from all CAD systems and STEP viewers handle layers the way NX does, and a lot of them do not even support the concept of layers at all. How the receiving system will react on a STEP file with objects on layers with different status is hard to tell in general. As a reference 2 in house systems where used to test this, Teamcenter Visualization and Solid Edge. Both of them show all objects as visible when the STEP data were imported, both what was originally resided on visible and invisible layers. You can manually hide the objects that originally were on an invisible layer, but that is done with a different concept than layers in these receiving systems.

A conclusion of this might be that a safe approach to get the same visual result in the system importing the NX STEP file as you originally had in NX, is to only have the visible objects to come across when exporting NX data to STEP AP203/214. The way to do this is to use Layers Selected filtering, under the Data to Export tab in the export STEP translator UI, and only include visible layers.


Layer 35 have been excluded in the menu by entering 35 in the "Disable Layer" field and pressing <enter>. Layer 35 is invisible in the current NX session.




Please note: If you are exporting the NX part file using STEP242 translator the layer handling approach is somewhat different in this translator. Our NX to STEP AP242 translator only translate visible layers to STEP. So objects on invisible layers are not translated at all even if those layers are included in the layer mask of the STEP translator.

Notes and References

Hardware/Software Configuration

Platform: INTL64
OS: window
OS Version: 10_1709
Product: NX
Application: TRANSLATOR
Version: V12.0.2
Function: STEP_AP214

Ref: 001-9405800