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Option to Import STEP file as Inseparable Assembly by Default

Option to Import STEP file as Inseparable Assembly by Default

1. Describe your environment: What is your industry? What is your role in your organization? Describe your stakeholders.
Machine automation. Admin for Creo and Windchill. All Windchill users within our organization.

2. What version of Creo Parametric are you currently running? and Windchill


3. Describe the problem you are trying to solve.

Due to the HUGE system/performance benefits of Inseparable Assemblies in a Windchill environment, we would like to have the ability to default to Inseparable Assemblies when importing STEP files. This would require 2 changes:

  • Add Import as Inseparable assembly to STEP file import menu
  • Add a setting to allow choosing Inseparable Assembly as the default.

4. What is the use case for your organization?
We get STEP files of customer data that can contain 100's or 1000's of parts, and since we reference their data in our machine design we often want to check this data into Windchill. TWICE in the last month we had users check in assemblies with 5000+ new objects pausing our Windchill system for 15+ minutes for all users while the check in completes. These large assembly check ins are made 3x+ slower by using the 'Auto Associate upon Checkin' that creates WTParts.

5. What business value would your suggestion represent for your organization?
Being able to protect our Windchill system by default rather than having to constantly train/remind users to remember to use available tools. Better performance for pretty much all things PDM:

  • Significantly faster check in
  • Less clutter in workspace
  • Less objects to refresh in workspace
  • Less publishing (1 file instead of 100's or 1000's)
  • Users can always unembed files if they need to create separate files.

Creo Idea - Import STEP as Inseparable Assembly.png

Windchill Check in Performance of STEP file assembly.png

When importing STEP assemblies, please also fix the extra assembly Creo creates and when possible don't append extra things to the end of the file names.

Creo Idea - Fix STEP File Import for Assemblies.png


We also approve this suggestion. We don't use Windchill but really would like to have the possibility to choose or foce inseparable assemblies when importing, and also avoiding having the redundant extra sub-assembly and file name extra characters (considering the very lmiited number or characters and filenames). I think the extra characters in filenames would only be needed for "Flexible" assemblies (same assembly filename with varying dimensions, parameters, components, etc). In regular assemblies, it does not make sense to append extra characters.

Community Manager
Status changed to: Acknowledged

Thank you @lhoogeveen for your well documented idea. Based on the information you provided, we are acknowledging it as the Community management team. This is not a commitment from the Product team. Other users may comment and vote your idea up.


have you tried to set the hidden entry intf3d_in_as_part to yes?

if you import a stp file you have to choose part or assembly.

for most stp files it is working, the parts stay in position.


or you can use inseparable assemblies. How to Create an Inseparable Assembly (And Why You’d Want To) | PTC
to use this you have to set enable_insep_asm_operations to yes.

Status changed to: Under Consideration

Hi all,


This is an interesting request and I understand the use case.  As described by @Peter below, there is an option to convert a STEP assembly into a multi-body part (hidden config) or the ability to convert an STEP file (once imported) to an inseparable assembly.  However, to make it inseparable, you would have had to import it first into Creo.


I would imagine you would prefer to keep the assembly structure intact and thus the desire to make it inseparable.  Provide the ability to convert to inseparable upon import.  We will review this request and consider it for a future release of Creo.


On a separate note, we are also evaluating the ability to make the hidden option to convert STEP assemblies to a multi-body part a supported option.  This would also be true for other formats as well.



Mark Fischer

Sr. Director, CAD Product Management 


This would be very good to implement.

I often get huge assemblies (1000s of parts) and then updates to them later on. With inseparable I don't have to change names that may be duplicated in Windchill. I also need to keep it as an assembly, not a compressed part as I need to remove certain components now and then for my part of the work.