STP export - Change in behaviouir between Inventor versions

[MattH_Work]

User has just upgraded from Inventor & Mechanical 2019 to 2024

IPT's ( with visible sketches ) exported as STP from Inventor 2019 work as expected when imported into AutoCAD Mechanical 2019 ( ONLY Solid & Sketch geometry ( wires? ) are visible )
When same file is exported from Inventor 2024, there is additional ( unexpected / unrequired ) geometry, namely the Centre Point

On the left is a STP export/import from 2019, on the right is the same file exported from 2024
As you can see there is an extra dot

In the 'real world' the AutoCAD Mechanical file is used to drive an engraving machine, so the user does not want any addition geometry

Experimenting with multiple versions, it seems Inventor 2019, 2020 & 2021 did not export the centre point, whereas 2022 onwards ( 2022, 2023, 2024 ) does

Why the change in behaviour between 2021 and 2022?

[MattH_Work]

The following may be related / unrelated or just a Red Herring...

Comparing the resulting STP files in notepad I have noticed a discrepancy

I ‘ think ’ ST-DEVELOPER is the 3rd party code Autodesk uses for creating the STP files, but the version number is not consistent with version of Inventor

2019 created STP using ST-DEVELOPER v20

2021 created STP usin ST-DEVELOPER v18.1

2022 created STP usin ST-DEVELOPER v18.1

2023 created STP usin ST-DEVELOPER v19.2

2024 created STP usin ST-DEVELOPER v20

Wouldn't one expect the ST-DEVELOPER version number to stay the same or increase with each new version of Inventor, rather than jump around

( just a thought, is 2019 using v20 as it was installed on my machine 10 minutes ago JUST to test this issue, is it hijacking the ST-DEVELOPER version that my Inventor 2024 installed ' way back when' )

[JDMather]

What STEP version are you using?

Otherwise... 

would it work for you to turn off AutoProject of Origin (or simply delete)?

[MattH_Work]

I've used 214 for all my trials ( exporting from 2019 through 2024 )

Also tried 242 from 2024 had had the same issue

2019-2021 DON'T export the additional points

2022-2024 DO export the points

[MattH_Work]

User has already considered

     turning off autoproject,

     deleting point from each sketch,

     deleting the points once the file has landed in AcadMech,

As the previous behaviour was expected / wanted, the end user would like to know if it can be changed back

[johnsonshiue]

Hi Matt,

I just tried exporting a simple part to STEP on Inventor 2019.5 update. The ST-Developer version is 17.2. I don't think it should be anything higher than that.

Many thanks!

[MattH_Work]

Seems I exported from 2024 and overwrote the existing 2019.stp ( my bad ) rather than creating new 2024.stp

So...

2019

ISO-10303-21;
HEADER;
/* Generated by software containing ST-Developer
* from STEP Tools, Inc. (www.steptools.com)
*/

FILE_DESCRIPTION(
/* description */ (''),
/* implementation_level */ '2;1');

FILE_NAME(
/* name */ 'D:\\2019.stp',
/* time_stamp */ '2023-11-06T09:00:33+00:00',
/* author */ ('matth'),
/* organization */ (''),
/* preprocessor_version */ 'ST-DEVELOPER v17.2',
/* originating_system */ 'Autodesk Inventor 2019',
/* authorisation */ '');

2021

ISO-10303-21;
HEADER;
/* Generated by software containing ST-Developer
* from STEP Tools, Inc. (www.steptools.com)
*/

FILE_DESCRIPTION(
/* description */ (''),
/* implementation_level */ '2;1');

FILE_NAME(
/* name */ 'D:\\2021.stp',
/* time_stamp */ '2023-11-02T12:19:39+00:00',
/* author */ ('matth'),
/* organization */ (''),
/* preprocessor_version */ 'ST-DEVELOPER v18.1',
/* originating_system */ 'Autodesk Inventor 2021',
/* authorisation */ '');

2022

ISO-10303-21;
HEADER;
/* Generated by software containing ST-Developer
* from STEP Tools, Inc. (www.steptools.com)
*/

FILE_DESCRIPTION(
/* description */ (''),
/* implementation_level */ '2;1');

FILE_NAME(
/* name */ 'D:\\2022.stp',
/* time_stamp */ '2023-11-02T12:17:48+00:00',
/* author */ ('matth'),
/* organization */ (''),
/* preprocessor_version */ 'ST-DEVELOPER v18.1',
/* originating_system */ 'Autodesk Inventor 2022',
/* authorisation */ '');

2023

ISO-10303-21;
HEADER;
/* Generated by software containing ST-Developer
* from STEP Tools, Inc. (www.steptools.com)
*/

FILE_DESCRIPTION(
/* description */ (''),
/* implementation_level */ '2;1');

FILE_NAME(
/* name */ '2023.stp',
/* time_stamp */ '2023-11-02T12:15:05Z',
/* author */ ('matth'),
/* organization */ (''),
/* preprocessor_version */ 'ST-DEVELOPER v19.2',
/* originating_system */ 'Autodesk Inventor 2023',
/* authorisation */ '');

2024

ISO-10303-21;
HEADER;
/* Generated by software containing ST-Developer
* from STEP Tools, Inc. (www.steptools.com)
*/

FILE_DESCRIPTION(
/* description */ (''),
/* implementation_level */ '2;1');

FILE_NAME(
/* name */ '2024.stp',
/* time_stamp */ '2023-11-06T09:04:49Z',
/* author */ ('matth'),
/* organization */ (''),
/* preprocessor_version */ 'ST-DEVELOPER v20',
/* originating_system */ 'Autodesk Inventor 2024',
/* authorisation */ '');

2019 ( I assume 2020, not tested ) & 2021 do NOT export the point

2022, 2023 & 2024 DO export the point

2021 & 2022 use the same ST Developer version, so that alludes to the issue NOT being directly related to the ST Developer codee

Is it an option somewhere?

I have attached files if they are of any use

[johnsonshiue]

Hi! Many thanks for sharing the file! I did verify that on 2021, the point does not get exported to STEP. 2022 and later do export the point. I suspect this was done as an enhancement request. On Import, you may uncheck Points so that the points are not included in the imported model.

Thanks again!

[MattH_Work]

AutoCAD Mechanical's 'StepIn' command does not have any options, so you get everything

( AcadMech is the final destination for the file )

It makes little sense, exporting to STP from Inventor, import back into inventor ( with points switched off ), to then export as STP again ( without points )