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SimScale Import of OnShape CAD

MarkInPTMarkInPT Member Posts: 6
edited July 2017 in Community Support
I am running into an issue that I hope someone can shed some light on. SimScale lets me import OnShape drawings directly into SimScale. However, when I do this, a smooth pipe drawing becomes faceted. Is this a limitation with the STEP import? If I export to STEP and then import the file, the same result occurs. IGES is also the same. However, if I export a fine STL file, the object looks fine in SimScale but then there are no faces to assign inputs and outputs. 

Also, if I import the STEP file into a CAD viewing software such as GrabCad, I still see the faceted surface so it looks like OnShape is exporting the drawing with these flat surfaces even though the drawing in OnShape looks completely smooth.

I am just trying to figure out if this is an OnShape issue or SimScale.

OnShape Drawing:

 Imported into GrabCAD

SimScale Drawing:


Best Answer


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    NeilCookeNeilCooke Moderator, Onshape Employees Posts: 5,449
    What happens when you import it back into Onshape? What you are seeing is display faceting not the surface. Probably looks worse in SimScale because they are probably trying to reduce the number of triangles they render online. Should not affect your simulation. 
    Senior Director, Technical Services, EMEAI
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    MarkInPTMarkInPT Member Posts: 6
    Thanks for the response.

    When imported back into OnShape, it looks fine (i.e. without facets).

    But I think it does affect the simulation in SimScale because the mesh looks just like the imported geometry with flat facets. I have asked the same question over there as well.

    What concerned me was that GrabCAD looked the same as SimScale so I assumed it was something to do with the export. I would expect some small rendering artifacts but if you look at the picture, they use 16 straight lines to represent a circle which is very crude.
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    MarkInPTMarkInPT Member Posts: 6
    Ok thanks, I will focus on SimScale as the culprit.

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    Hello @MarkInPT ,

    This is Sam from SimScale Support! Can you please direct me to your document? If possible kindly share it with srajendran@simscale.biz.
    I can check the issue and get back to you at the earliest possible. We need to investigate further as to the reason for the problem occurring with SimScale platform and other tools as well.

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    MarkInPTMarkInPT Member Posts: 6
    Both are public documents but I sent invitations as well for both OnShape and SimScale projects.

    Thanks for your help.
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    Hello Mark,

    Thank you for sharing the document and SimScale project. I see that the issue is caused due to minor regression on our end.

    We have fixed the problem. Please import the CAD again from OnShape and it should work now as usual.

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    MarkInPTMarkInPT Member Posts: 6
    It looks like it is fixed now. Thanks!
  • Options
    MarkInPTMarkInPT Member Posts: 6
    This problem has returned with the latest SimScale update.
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