File Size difference Mac - Windows

when i open a file from a windows version and without changing anything just saving it, a file which has ~ 350 kb becomes something like 3 mb. anybody noticed, or did i set something wrong?

yeah, something is odd.

if i open a new file… draw a _Box…

the file size is 2.7mb.

I see this behavior. Logged in MR-3068. Thanks for reporting this. We’ll take a look.

Dan, I added one this morning as well, from a S’bee conversation -


hi @marlin i see that this will not be fixed, but a “suquestion”: if its about saving time and rendermeshes are causing the file size, would it make sense if the rendermeshes are not stored at all and just created when opening a file? if possible, less storage and saving even faster.

Might make saving faster, but opening slower, as creating render meshes takes time - sometimes a lot of time if the mesh is complex or you have a lot of objects…

If you don’t want to save render meshes, you can always use SaveSmall.


yes but creating meshes takes place in the ram or even video memory i assume, writing out a file involves slower memory. and save small still creates a big file as i just tried.

If SaveSmall is still creating a big file, then the file size is not due to display meshes, but something else. Or SaveSmall is broken on Mac.


Mac Rhino does not compress meshes or bitmaps stored in a 3DM file; Windows Rhino does compress both meshes and bitmaps. In the simple model in this thread, the preview bitmap takes about 2.5 MB and fills up almost the entire contents of the Mac 3DM file.

Compressing bitmaps and meshes takes about 90% of the time to save a 3DM file. For one user’s file that contained bitmap images along with render meshes, the file save time dropped from 26 seconds to about 2 seconds. This kind of real-world performance improvement is critical for making Auto Save efficient and invisible.

Hmmm… it sounds like I would not want to find out what my 3.5 GB Windows files would look like on Mac.

Ah, that explains it. Perhaps SaveSmall could have the option to nuke the preview… --Mitch

original file ( OT: 2 years and a half of work): 94 BackgroundBitmap, 5 PictureFrame, 1.36gb size. the file is open: 15 “- 38” (the first time with a few objects in the scene, the second time with all the objects in the scene)
copy-paste files: 94 BackgroundBitmap were present, were removed with _TestPurgeBitmapTable command (in the past has NOT worked)
At this point the file was reduced to 1.17gb. Opening time 33 "with all the objects in the scene.

Autosave time fell in my case from about 30 “to 2” after enabling trim terminal on the external SSD hard drive used for boot. The day when I did it I cried.