Autocad Export .iges Significant Figures

[Anonymous]

I have a 2D drawing that I need to export as an .iges file for use in Ansys Workbench. My drawing has a section with two concentric arcs that are very close to one another. In the drawing they look like sections of a circle (as they should and are), but after I export the drawing from Autocad the curves are now just line segments. I'm not sure if I can export the .iges file with curves, but can I somehow at least export the curves as segmented lines of smaller size? I think I have a significant figures problem, and while I can see information on changing the significant figures for .iges exporting in Autocad I can't find the menu to actually change the significant figures. Does this even make sense?

I've attached the .dwg and .iges files.

Can someone please help?

[john.vellek]

Hi @Anonymous,

When I opened your DWG, I noticed from a popup that it was not created in AutoCAD. So, I used EXPORTTOAUTOCAD to write it out to a pure AutoCAD DWG. I opened that file and set viewres to 20000 so I could verify the arcs looked correct. Then I ran the Export to IGES format. I opened the resulting file (attached) and opened it in Fusion 360 and the arcs do look like arcs.

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

[Anonymous]

Hi @john.vellek,

The you created from what I posted yesterday doesn't seem any different. I still see a few line segments that comprise the curves in my .dwg file. I tried following your process and got the same results. I don't know what's going on. Maybe there's a difference between your Autocad settings and mine?

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@john.vellek wrote:

Hi @Anonymous,

When I opened your DWG, I noticed from a popup that it was not created in AutoCAD. So, I used EXPORTTOAUTOCAD to write it out to a pure AutoCAD DWG. I opened that file and set viewres to 20000 so I could verify the arcs looked correct. Then I ran the Export to IGES format. I opened the resulting file (attached) and opened it in Fusion 360 and the arcs do look like arcs.

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

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[john.vellek]

Hi @Anonymous,

As you can see in  my image that I attached, the curves are retained in the IGES file. So, the question is what application are you using to look at the IGES file?  I think  the problem is there and not in the output from AutoCAD.

I tried my file in Inventor as well and it still has the curves. I have attached the Inventor part file for you to examine also.

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

[Anonymous]

I've opened the .igs file you sent in both Solidworks and Ansys Worbench DesignModeler. Both files show the line segments where the two curves should be. I imported the .igs file into Inventor, and the curves show up just fine. The problem could very well be with Solidworks and DesignModeler. I have no idea how to fix the problem, though.

[john.vellek]

Hi @Anonymous,

From what I am reading (briefly) on the Solidworks forums, this is not an unusual thing.  It appears to happen because of the way Solidworks interprets the data upon import.  One of the suggestions that  seems prevalent is to use STEP  or Paraolid formats in lieu of the IGES.

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

[Anonymous]

I've tried .stp and .sat files today. I don't know if the problem is with Solidworks or Ansys Workbench DesignModeler. Currently, I don't know what my issue is, but I don't think the problem is with Autocad.

I'm still stuck, but I appreciate your help so far!

[john.vellek]

Hi @Anonymous,

Have you posted this question on the Solidworks forums?  i don't think there is anything all that unusual about your drawing file so there must be something that needs to be done on that end.

Did you try importing the file from Inventor into Solidworks?

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