Exporting from rhino to solidworks and prototyping(cutting on cnc 5 axis machine)

Hi guys, i have an issue where i have a model i created in rhino and tested it with the volume analytics and surface edges and naked edges and it all checks out ok. i want to import it into solidworks but when i do i have errors which take forever to heal. is there a specific way to do this and get best results? also this file will be cut cut on a cnc 5 axis machine so what format is best for this since my model is already watertight and all set to go from rhino 5. are files made in rhino good to go for cnc prototyping?

Hi Mitviz,

If you export as STEP and then re-import in Rhino, is it still a valid closed polysurface?
If so, there’s a good chance the program used to generate the toolpaths will be able to digest it too.

This is interesting, i tried this and for sure i had issues and i ended up with errors after opening, why would rhino do this? are poly surfaces nurbs?

Well what sort of errors are there? Are they in the original Rhino model? (Use SelBadObjects) to look.

Of course, do you want to hear a dirty little secret? It may machine just fine, CAM doesn’t actually need a watertight solid, though the errors may indicate it wasn’t modeled properly.

there are no errors in the original rhino model and i was checking as i was going along and i didn’t use select bad object i check for naked edges and made sure it had volume but in about an hour i will run that check you suggested.

Thanks for the tip!! i am hoping all goes fine with the models i prepared

ok verdict is in! no errors are reported in my original model so idk if rhino is messing with me or what. Is rhino considered a tool of less quality than solidworks? i want to know how people work in industry


You haven’t answered this one:

That is, what sort of errors do you get when you import your STEP back into Rhino?
Can you post an example file? Alternatively, please send a sample to tech support at McNeel.


really sorry about that and thanks for noticing as this is important. what happens is when i import the step file back into rhino it comes in as a block and then i explode it which gives me this message you see in the attached picture

idk if i can post the file since the project is ongoing but it seems i can send it to tech which i didnt want to do because sometimes like over at solidworks forum it takes weeks to get a reply when you upload files to tech

All that dialog is telling us is that there are errors, not what they are. You need to actually check the objects to see what it says (which will probably be incomprehensible, but errors fall into a few basic categories.)

This isn’t Solidworks, it doesn’t usually take weeks to get a reply from tech support.

Have you used JoinEdge to join any naked edges in your model because that can cause problems.


ok after explosion i ran the check command and i got this

also i just sent the file to techmcneel to see what can happen

no i didnt use join edge for naked edges

Have a read through this KB support page:

When you save as STEP and when you read a STEP file, whatever software is used, you’re translating twice the data.
With each translation there’s a possibility of errors sneaking in. You can check what’s going on; open the STEP file with a text editor, you’ll see what’s involved. These file formats are not particularly robust (I don’t think there’s error-checking built-in like ausio or video files for example).
If you send the original Rhino file to McNeel tech support they can improve the STEP translator to better cope with this case.
You can also sent the STEP file to SolidWorks, they’ll look at it in a few months and you won’t get feedback but it may help them in the future.

Well its good am getting some reply from you guys here, i really prefer it here and rhino is a really kool software, i think its the only software i used that never crashed. am learning more and more but the whole confusion about file types nurbs and surfaces really bugs me out, i found out today that the step files i export from rhino really worked well for the cam guys so now i am happy, no need for solidworks.

And, like any software known to mankind, there are ways to get Rhino to crash. It’s just a lot more difficult than most, especially CAD software.