Inventor Error - Region Properties Function

[friskney]

Inventor The 2019 REGION PROPERTIES function gives a wrong principle axis alignment.

The 2018 gives sketch axis and principle axis at correct angles.      

The 2019 gives both axis aligned the same.    

See the attached screen shots of 2018 and '19

This error is apparent when the function is run on a non symmetrical section.  

I am hoping autodesk fix this error in the measure/REGION PROPERTIES function

[kelly.young]

Hello @friskney I see that you are visiting as a new member to the Inventor Forum.
Welcome to the Autodesk Community!

Can you try to Insert Photos again, the images you refer to did not get uploaded and would be helpful with investigation.

Please select the Accept Solution button if a post solves your issue or answers your question.

[friskney]

Aligned axis [2018]

kelly.young has embedded your image for clarity.

[friskney]

non aligned [2019]

kelly.young has embedded your image for clarity.

[Fawlters]

Probably related to this, one of my colleagues noticed that 2020 gives different results depending on the sketch plane orientation relative to the part origin planes. Sketch and principle axes are still aligned in 2020, as with 2019 for @friskney 

Using the XY plane, 2018 and 2020 region properties give the same results, which suggests the calculation is using a fixed reference plane, not calculating relative to the sketch plane as would be expected.

Comparison screengrabs below:

2020 XY, XZ, YZ planes, all give different results.

2020 XY plane2020 XZ plane2020 YZ plane

2018 Screengrabs, XY, XZ, YZ planes, all give the same result:

2018 XY plane2018 XZ plane2018 YZ plane

[friskney]

Autodesk are aware of this problem and have made their error worse.

Inventor 2019 & 2020 is giving incorrect Section properties.

THIS IS DANGEROUS

If a catastrophic failure results, I think Autodesk may be found negligent.

Why won't they fix their error?

[johnsonshiue]

Hi Guys,

Many thanks for reporting the issue! It issue is known as INVGEN-30902 and INVGEN-31298. The latest status shows that they have been fixed in internal build. I am working with the project team and see if the fix can be ported back (some can but some cannot). Hopefully, the fix will be available in the applicable updates soon.

Regarding the wrong values, it is bad for sure. Inventor team or Autodesk as a whole never intends to produce the wrong values. It was a coding mistake like any defect in human-made product. We try our best to avoid a defect and also try our best to fix it when found.

Thanks again!

[Anonymous]

Hi Johnson,

Do you have any update on this after 6 months? Engineers that are unaware of this problem will be making critical design decisions based on incorrect data provided by Autodesk software.

[johnsonshiue · Accepted solution]

Hi Guys,

The defect has been fixed on 2020.2 update and 2019.4.3 update. Please install the updates accordingly (2020.2 followed by 2020.2.2 or 2019.4 followed by 2019.4.5).

Many thanks!

[JamesSlaven8282]

Hello.

I am experiencing similar behavior to this topic with sketches in the drawing environment using v2024.0.1.

The screen attached shots show a sketch created within a drawing base view with projected geometry from which I am trying to get area measurement using Region Properties.

The visible driven dimensions are inches (FYI).

If anyone has info or can advise on this please share.

Thank you,

James

[johnsonshiue]

Hi James,

It should just work. Is the actual part very far away from the origin? Please share the files here. I would like to understand the issue better. This is different than the OP's problem.

Many thanks!

[JamesSlaven8282]

Hi Johnson,

I tested this using two different PCs running Windows 10 and Inventor 2024.0.1 with same result. The attached part file consists of a 1"x1"x1" cube modeled about the origin and is the base view on the .dwg drawing attached. For this I used a standard Eng .dwg template but the behavior occurs using any template.

Steps:

1. Place the base view

2. Start a sketch within the view

3. Project the edges for a closed profile

4. Select Region Properties and choose the projected closed sketch region.

5. Choosing Calculate produces the alert :  "Measure: problems encountered while executing this command.
The attempted operation did not produce a meaningful result. Try with different inputs."

6. Selecting OK produces the results shown in the attached ,jpg screenshot.

I have used this procedure through the years and across many versions. I cannot think of anything I may be doing differently now or what may have changed during our last upgrade from 2023.

Thanks and Regards,

James

[johnsonshiue]

Hi James,

Many thanks for sharing the files! This is absolutely a bug. It seems to start from Inventor 2024. It should just work. I will work with the project team to understand the issue better. Hopefully, it will be fixed soon.

Thanks again!

[dmaloneP6UFR]

Hi All,

Have just discovered the ongoing issues with Region Properties errors in Inv.2026. Please see attached screenshots of an example I've quickly made up. No changes to section properties when the section is rotated around the sketch origin. No change to reported rotation angle to principal axis.  Same issue in 2023.5.

As others have noted, I believe this needs to be addressed urgently as engineers are using this tool to facilitate design decisions. 

Cheers

DM

[johnsonshiue]

Hi! I vaguely remember having the discussion with the project team about the behavior. The moment of inertia of a square remains unchanged when the centroid is located at the origin due to its symmetry. This isn't a bug.

Many thanks!

[dmaloneP6UFR]

Hi John,

Thanks for your reply. My mistake- I overlooked that. 

Cheers
DM