Reduce Rhino file size

I have tried to reduce a file size and I have deleted all the elements that I didn’t want and then purge the file however it would not reduce to a reasonable size (40M) for just a small 3D step model. I have then copied the 3d model and pasted it to a new blank file and saved it as a separate. The size of this file is more reasonable for the model (2M). I have deleted all the elements and layers of the previous file and it would still show a massive file size (40M) and I don’t understand why, I go to ‘Select all objects’ and I get the response saying there is nothing to select so I assume the file has no objects but it still has a massive size so where does the size come from? Is there any other way to reduce the file size instead of copying and pasting to a blank file?
Thank you


Hi Mikel,

A possible reason is that the file contains that much data from one or more plugins.
Do you have plugins installed?
Are some object hidden?
Might there be block definitions still in the file?

If not, I think it would be good to send the file to McNeel.
I have had a file recently that also was extremely bloated for it’s geometry, however I was in a hurry did not save the file to upload for inspection.

You can always upload files here:


Did you try the _purge command that should delete all unneeded block definitions.

Hi Willem
Thanks for your reply.
I have just uploaded the file. It is just a 3d model of steps (Escaleras2), I have deleted everything else and left only the steps however the file size remains far too large.
Yes I do have some plugins I have used Grasshopper to generate some features of the model. I have already deleted these features though, could they still have an effect on the size? I noticed while I was using GH on this file that the computer would slow down considerably, but I never had this problem using GH on other files.
I have also used blocks but again I have deleted them, how can I delete any definitions that might be left?
How do I look for hidden objects in rhino?

Hi Micha
Thanks, yes I have used purge and it has deleted some unused stuff but unfortunately little effect on size.

Try -SaveAs (with the dash) and check SaveSmall=Yes and SavePlugInData=No

Does that help?


Hi Mitch
Thanks but I don’t get the ‘SavePluginData’ option when I go to Save As? I see three options: save small, save geometry only and save textures. Should I look somewhere else or am i missing something?

Yep, the file has masses of plug-in data- the objects, without plugin data (_-SaveAs etc as described by Mitch) and without the embedded image file (4MB, use testPurgeBitmapTable to remove it if needed- note the command will remove all embedded bitmaps so be careful) is about 300 K. Also, the obiects are very far from the origin, the meshing is terrible- move them to the World origin if you can.



Hi Pascal
I was missing the dash!
So yes, it works! Thank you!

but are you sure that “SavePlugInData=No” doesn’t delete anything?

Hi michtat- it deletes plug-in data in the saved file, not the current one. If you are using rendrering or CAM plug-ins, etc in the file, this info will be lost.


After doing save smalls, a Rhino3D file can be compressed to about 25% of its original size with 7Zip. I always use maximum compression, with a non-solid achieve, which is safer than a solid one, in case you have a drive crash.

Dear McNeel, this would be a great option from the save menu. filename.3dm7z Nudge, nudge, wink, know what I mean : )

Is storage really a problem? I often work with files from 0.5-1.5 Gb, and there are quite a few of them on my 1 Tb mechanical hard drive, along with hundreds of others in smaller sizes… In general the only reason I compress stuff these days is to upload it to someone/somewhere…


Old versions are helpful for reversions, perhaps even for legal purposes.

A few versions each day, add up. Twenty-five percent is a great reduction in file sizes for files that are rarely used, and need to be backed up. My design folder is 20GB, but one project is 16GB of that, and for that I 7Zip achieve every 100 versions. I want a SSD for my laptop, but need a 1TB, which is expensive enough that I can’t afford one yet.

Dunno, for archiving little used files, you can have a 2 Tb external drive for under $100. Not saying compressing files isn’t useful, just not really essential…


I had something related to solids being made from a bad surface that had hundreds of points.
Because of this, I had a lot of solids which had this surface.
The file was in about 200 MB !
But then I applied the “ShrinkTrimmedSrf” to the solids.
Indeed if on a later stage you wish to untrim… that will be of no use…
But… Now I have less than 50 MB for that file.


I missed a compression option too. My project files are around 1.5GB often and I use incremental save. Best pack results I got with RAR archives.

Micha, in tests Rar edges out 7zip, but in price and cross platform use 7zip wins. What compression did you get with Rhino files BTW?

Helvetosaur, I am accepting donations for a 1TB Samsung SSD at 850 at $579. I also need a 1TB backup drive. I can use one the old one from my laptop as the other. My bare minimal backup is well over 130GB. I have over 564 GB used on my drive. It would be higher if I didn’t compress my Rhino files.

As I wrote, a compression option would be a good option for people who make a lot of progressive changes in a single file. I would bet 1$ that more people would choose to use an compressed save option, than the idle processor that is in Rhino, currently.

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+1 for Compression Option.
I’ve found that on a file that was saved using the “Save Small” (No Meshes) option 7Zip (with 7z format) gets much smaller files than RAR or ZIP compression.
Thus I would recommend that a compression option automatically enables SAVE SMALL in the background before compressing.
Compression is a common option in image formats.
eg. PNG and TIFF can be saved with or without compression applied - Michael VS

Better not. Size isn’t the only goal. Saved meshes help to avoid long remeshing of complex models. If a model is 600 MB and the mesh is 60MB, than it is no problem for me to save the mesh. (I expect the file is 60MB as RAR-Archive.)