topic Exporting to step, accuracy problem in Inventor Forum

Exporting to step, accuracy problem

adrianos_filinisC9K3S — Thu, 18 Apr 2024 15:20:33 GMT

Hello,

I am trying to export a model to step file and increase the accuracy as much as possible because it will be machined in CNC and I need high accuracy.

When exporting I choose options and increase the spline fit accuracy to the maximum which is 0.00001cm.

When the file is imported to Creo ProE the accuracy goes down to 0.01mm, and checking as well the UNCERTAINTY_MEASURE_WITH_UNIT(LENGTH_MEASURE(0.01),#88060, it is 0.01 even though I increased the accuracy.

Do you know how I could solve the accuracy problem I am facing?

Thanks,
Adrianos

Re: Exporting to step, accuracy problem

CGBenner — Wed, 10 Apr 2024 11:01:28 GMT

@adrianos_filinisC9K3S

Welcome to the forum. Could you possibly share one of your exported STEP files (something safe to share), so experts in this forum can look at this? I wonder if the issue is on the CREO side... but we would need to look at the STEP file itself before pointing fingers. 🙂

Re: Exporting to step, accuracy problem

adrianos_filinisC9K3S — Wed, 10 Apr 2024 11:06:05 GMT

Hello,

Thanks for the response.

I have updated my post with the model in stp format.

Best regards,

Adrianos

Re: Exporting to step, accuracy problem

johnsonshiue — Wed, 10 Apr 2024 23:36:17 GMT

Hi! If I understand how STEP format works correctly, the UNCERTAINTY_MEASURE_WITH_UNIT setting in the STEP file is about the maximum tolerance allowed (not exceeding) in the exported file. The Spline Fit Tolerance when the STEP file is exported from Inventor is about the minimum tolerance of fitting a spline curve. These two are not the same.

Many thanks!

Re: Exporting to step, accuracy problem

adrianos_filinisC9K3S — Thu, 11 Apr 2024 11:52:07 GMT

Thanks, though I still dont know how to increase the UNCERTAINTY_MEASURE_WITH_UNIT.

That is my goal. Do you have any advice?

Re: Exporting to step, accuracy problem

johnsonshiue — Thu, 11 Apr 2024 18:26:39 GMT

Hi! I don't think Inventor allows that value to change. The maximum tolerance of 0.1mm is quite loose already. What do you want to change it to? Any bigger value could lead to bad geometry and modeling failure.

Many thanks!

Re: Exporting to step, accuracy problem

adrianos_filinisC9K3S — Fri, 12 Apr 2024 08:25:38 GMT

So their no way to increase the accuracy of the exported file by decreasing that number?

My part is going to be machined and it comes out faceted when imported from the engineer in their system.

Re: Exporting to step, accuracy problem

johnsonshiue — Thu, 18 Apr 2024 14:56:01 GMT

Hi! Indeed, I don't believe there is a way to tighten up the tolerance other than Spline Fit Accuracy setting on STEP Export. I am working with the project team to understand the behavior better. In the meantime, please share the Inventor files with me directly johnson.shiue@autodesk.com.

Many thanks!