Obj export extremely slow



Hi there!

I am experiencing a slowdown very hard here while exporting simple obj mesh from Rhino 6.
It takes a long time to export files into obj, while Rhino 5 was fast.

I mean, for a 10Mb final obj file it took 10 minutes to save. This is not normal.
It takes time even if I have already previewed the mesh.

I don’t know,I am using the same setup as Rhino 5, but here it takes ages.
Am I missing something? Could it be a bug?

Thank you everybody and have a nice day


(Pascal Golay) #2

Hi filippo - by previewing the mesh, do you mean you meshed the object first in Rhino (Mesh command) then exported the mesh directly? Or is the meshing for the obj taking place as part of the export process. It would be good to know if the delay is in the export or in the meshing part.



Hi Pascal!
I’ve just tried to export objs in three different ways and it is always slow.
The procedure I used were:
1- straight export from nurbs, without previewing the mesh:
2- stragiht export from nurbs, previewing the mesh from the polygon mesh options;
3- meshing the nurbs in rhino, then exporting that meshes to obj.

For a file with less than 50 closed polysrf (not very intricated, final mesh has 50522 faces), and a final obj file of 7Mb it took almost two minutes to save.

Hope to be helpfull somehow!

Let me know if it could be usefull to share the files I am using.

Thank you for time.


Any news? The situation is going crazy here. It takes ages to save an obj.

Thank you guys

(Pascal Golay) #5

Hi Filippo- can you please send the Rhino file to tech@mcneel.com, to my attention? I’ll see if I can reproduce the problem.



(Mike) #6

Hi, I am also having the exact same problem. I’m working on a much bigger file and export times for an obj is huge. Would it have anything to do with the new ngon feature?

Thanks in advance for any help!

(Pascal Golay) #7

Hi MIke - can you tell if there is any difference if you do not check the box for ‘Create nGons’? I do not see any delays so far here.


(Mike) #8

I just tested it and it also took about 10 minutes for the export even with the ‘create ngons’ box unchecked. Another weird thing- the file that eventually did export with the ‘create ngons’ box checked would not import into 3ds max, the obj import process froze on the ‘building scene’ stage. The version that was exported with ‘create ngons’ box unchecked imported into max fine.


Sorry Pascal I haven’t had the time yet to prepare the file, but I still have the same issue. I will send you the file as soon as I have it ready! Thank you for your support

(Pascal Golay) #11

Hi Mike - if you can send us a file that is slow, that would be helpful - send to tech@mcneel.com, to my attention. The smaller the better, for troubleshooting, as long as it shows the problem. If the file is large, zip and upload to




(Jackthetaylor) #12

Has this been resolved?

I’m having the same problem, we’re having to export our files back to rhino 5 to export objs as the slowdown for multiple part exports is crazy! We’ve had this problem with multiple files as well. (largest file was 93mb total and only exporting a small section of this). I’ve noticed that rhino 6 also seems to have other slow downs on commands like undo and copy to clipboard and I was wondering if this is part of a larger issue

(Johannesrauch91) #13


currently evaluating Rhino 6, and noticed the same slow .OBJ-Export Problem.
After some fooling around i noticed something. I almost exclusively work with a networked shared drive, and export is only slow and writing only a few kB per second (30-40 kBps) when i export the File to the drive.

If I export to my local drive instead, Rhino writes the file almost instantly.

I have noticed something similar in other programs (i think autodesk Meshmixer suffers from this aswell). It’s weird because normal Read/Write on the network drive is 50-100mBps, maybe it’s how the files themselves are written which is not suited for network transfer.

I guess writing the file in larger blocks or save to the userfolder in blocks first and then transfer to save location might fix this, but i can just guess.

Just so you know that might be another factor that causes slowdown, it might not necessarily be something in the Rhino files themselves.

Hope this helps someone. Cheers!

(Pascal Golay) #15

Hello - thanks for the details… we are still trying to track this down - for at least some users the lag is there on local drives as well.