Strange behavior in meshing. Is this a bug?

[ryoichiUR6NW]

It is acceptable that the complex shape cannot be meshed. However, I think this case is bug or software specifications.

In case of single part Fusion can mesh it. Attached picture shows it. 

This picture shows that this shape is not complicated enough to make meshing difficult.

I attached rectangular to this model. Fusion can not mesh them. Attached picture shows it. This is the problem.

I joined 2 parts. Fusion can mesh it. Attached picture shows it. This picture also shows that this shape is not complicated enough to make meshing difficult.

In my job, joining is not my intention and I need to simulate with multiple parts. 

Could you give me some advice.

[dsouzasujay]

Hi @ryoichiUR6NW ,

The attached design, this has small "ridges" or features that would require a very small element.

I was able to successfully mesh after increasing the absolute size to 5 mm and providing "Local Mesh Control" to the small ridges.

Also attached the .f3d file for your reference.

[ryoichiUR6NW]

Mr. dsouzasujay

Thank you for valuable advice. But my concern is not small ridges. Fusion can mesh this model which includes small ridges as shown in left picture of meshing result.png that I attached. In this case local mesh control is not necessary. My concern is that meshing is not possible when there are multiple parts. The problem is that Fusion changes its behavior for single part and for multiple parts. Fusion360 cannot mesh multiple parts which can meshable in single part mode. So in this case avoiding complex shape is not solution, Fusion360 should change its behavior.

[dsouzasujay]

Hi @ryoichiUR6NW ,

Fusion 360 simulation mesh uses bounding box ratio to mesh Brep bodies.

When we have single part the bounding box fits the body, so the default absolute mesh size can mesh the part. but when we have multiple parts then the bounding box increases. we may need to reduce the absolute mesh size or we need define local mesh control.

[ryoichiUR6NW]

Thanks for the useful information. I learned about the relationship between the bounding box and the absolute mesh size. I downloaded the file(meshing_Pass_Sujay.f3d) that you uploaded and meshed it. Unfortunately my Fusion360 cannot mesh it. I attached the capture of meshing result. Would you please upload the f3d file that was successfully meshed again with a different file name? Please give me some time. I will look it up myself.

[ryoichiUR6NW]

Mr. dsouzasujay

Thanks for the useful information. I learned about the relationship between the bounding box and the absolute mesh size. I downloaded the file(meshing_Pass_Sujay.f3d) that you uploaded and meshed it. Unfortunately my Fusion360 cannot mesh it. I attached the capture of meshing result. Would you please upload the f3d file that was successfully meshed again with a different file name? Please give me some time. I will look it up myself.

[dsouzasujay]

Hi @ryoichiUR6NW ,

The attached file(meshing_Pass_Sujay.f3d) should allow you to mesh the file.

Please view screencast: https://knowledge.autodesk.com/community/screencast/8616964c-85aa-4e7a-8404-d0b4d1ddc090

[ryoichiUR6NW]

Mr. dsouzasujay

Thank you for responding me. I downloaded your file and opened it. My Fusion360 cannot mesh it.
Please view screencast:https://knowledge.autodesk.com/community/screencast/4f76deac-d473-4f0f-9ba3-89aef5a44d2e
Is my Fusion a different version than yours?

Regards,
Ryoichi

[dsouzasujay]

Hi @ryoichiUR6NW ,

Try uploading the file to the data panel and meshing it.

If it still fails try changing the absolute mesh size to 4mm and mesh.

[ryoichiUR6NW]

Mr. dsouzasujay

Thank you very much for your many replies.
I tried uploading the file (meshing_Pass_Sujay.f3d) to the data panel and meshing it with 4mm absolute mesh size. Unfortunately it failed.
Please view screencast:https://knowledge.autodesk.com/community/screencast/dcbab955-b2e3-4936-bf6f-61350badf072

I find out your Fusion360 is Mac version. My Fusion360 is Windows version. Is the difference of the version the cause of my problem?

Regards,
Ryoichi

[ryoichiUR6NW]

Did AUTODESK reproduce this behavior in the Windows version?
Would you please post to this forum if there is any progress?

[dsouzasujay · Accepted solution]

Hi @ryoichiUR6NW ,

I was able to reproduce this bug on a Windows machine, As you mentioned on macOS it is generating mesh.

Thank you for reporting this bug and appreciate your suggestions.

Logged a bug (FUS-79013)

[ryoichiUR6NW]

Mr. dsouzasujay

Thank you for your support.
I hope this bug will be fixed soon.

I do not require the meshing ability for very complicated shape.
Since this single part with complicated shape can be meshed, in this case, the complexity of the shape does not make meshing difficult, but if we add a simple rectangular, we cannot mesh them.

Regards,
Ryoichi

[dsouzasujay]

Hi @ryoichiUR6NW ,

Thanks for adding, Since this is part & OS specific we have added this bug to the backlog, development team is looking at the fix.

I will update here when the fix is available.