Autocad import really slow

Why are autocad imports so slow? What can be done to improve the situation?

They shouldn’t be - does this happen with all files, or just particular ones? What kind of elements are in the files you’re importing?


Thanks Mitch,I have this issue with all ACAD imports. I don’t notice it if it just a few lines. But if I bring three views of a boat (that views fine in ACAD) it is really slow and I have to put it on layers to turn things off so I can pan and zoom. Today’s issue is with a 2D engine drawing that once again views fine in ACAD but just parks once inside of Rhino. I have tried deleting the hatching and saving small and that did not seem to help. It is just lines and arcs, all be it a lot of them in the case of the engine file 14,000 entities. I am not alone, my coworker has the same problem. Any help would be greatly appreciated as this is a recurring issue for us. David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188

Is it possible for you to post a dwg file so we can try to figure out what the problem is?

i had a (somewhat) similar sounding problem a couple of days ago… i opened a 55MB model and it was literally 2 objects… a line and part of a sphere… and it was super slow to navigate… i couldn’t figure out where all the data was located in the model or why it was performing so slow.

turns out, the file’s render mesh setting were crazy high (the sphere was being showing with approx 4million vertices)… i turned off the custom mesh setting and everything went back to normal and file size dropped to the 150Kb range.

so, maybe something along these lines with you? (though maybe not if all you have is lines/arcs with no surfaces)

Thanks Gents,I have attached the file. David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188

slow acad (3.92 MB)

i’m on mac but maybe some relevance –

if i have my object properties inspector open while trying to move/select/etc, this model is very slow… if i close that panel, it’s much more responsive.

this is the panel on mac… so whatever the windows equivalent is, try turning it off?


OK, so it’s not the actual importing process that’s slow, but the dynamic video performance when panning, zooming and rotating?

Your 3dm file seems pretty OK here to me… On my laptop with a Quadro 2000 video card, it tumbles and pans about as quickly as I would expect for 29K curve objects…

Quick video - note some of the jerkiness is due to the video and not Rhino.


I also see good performance tumbling and zooming it. (much better here than what Mitch’s video shows)
So, there must be something special about your video card, video driver or display settings.
Easiest first - are you talking about default wireframe display mode?


Thanks Mitch,Yes, the problem is not importing (although that is not all that fast) but doing anything with it after words. For instance, cleaning this file up onto a few layers, rotating and moving into position was really slow. It took minutes when I moved the objects onto new layers. 29k curves may seem like a lot but this a common file for my work and I often need to bring in larger files for instance when modeling a boat from a full set of 2D drawings. These files are not slow at all in ACAD but are almost unusable inside of Rhino. Thanks for your help!Best,David David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188

Hmm, shouldn’t. Your objects are grouped, I ungrouped them, then selected about 5000 curves and changed them to a new layer - took about 1 second. Have you any non-standard plug-ins running?


that’s the same as i’m experiencing (when first opening)… ungrouping and navigating isn’t that bad… but what happens if you-> open the model, select a group, then try to _Move or drag it?
is that fast for you too? that’s when it super slows down for me (unless i close the object properties inspector)

Hi Lowell,Yes, just talking about wire frame view. d David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188

fwiw, here’s what i’m seeing…
(note- this is on a 2010 laptop… with not the best of graphics etc.)

i tried it earlier on my desktop and navigating was very fluid though this is still acceptable on the laptop… (also, screen capture software is going so that’s eating up some resources)

anyway, the screen capture software doesn’t capture the spinning beach ball and just shows a regular pointer cursor instead but the whole time the blank ‘drag’ dialog is up, the cursor is actually a spinning beach ball… (so, don’t watch from :30 to 3:00 because it’s nothing… dragging froze the app for 2.5 minutes…

in case it’s not obvious-- when first opening, the bottom inspector panel is set to command history… i can navigate/move/drag in an acceptable manner… i then change the panel to ‘objects’ which is when the mega-slowdown starts happening.

i get it that this isn’t entirely related to the topic as i’m not using the same software but maybe it is related? some sort of observer when dealing with 16000 lines in a selection is causing a slowdown?

otherwise, if that’s not the problem djb is having… this properties problem i’m showing probably needs to be looked at from a mcneel mac tech.

I get this sort of reference files for marine projects a lot and sometimes the dwg files have been ‘exploded’ and on an engine file that means tens of thousands of little tiny separate lines that each have to be dealt with by Rhino as a separate entity. To clean things up, first SelDups and you will be amazed at how many lines show up. AutoCAD drafters can be notoriously sloppy with many Dups from endlessly copy/pastes. While you are at it SelBadObjects and toss those. Then I turn each layer on one at a time and JoinCurves. This connects tons of little lines into one line. Some get joined together that shouldn’t be, but this alone will speed things up greatly. SelectSmall lets you get rids of tiny little insignificant crap that you really don’t need when using such a dwg as a template. There is a command that Pascal or someone gave me here recently that will let me put the whole thing in all layers on one new layer named ‘Engine DWG’ or something like that and retain their original colors which is a huge help. Sometimes it helps to explode all blocks so they can go to the new single layer as well. I usually do all of this clean up in a new file and then delete the now empty layers and get rid of the countless ACAD block definitions that are no longer of any use in Rhino and them copy the grouped or newly blocked template on its own simple layer into my working document. I hate having to do so especially when the next day the guy who gave you this slop makes a couple little edits and sends you a fresh pile of slop all over. I’ll look at you file and do my routine on it and see if my methods would help in this case.

Jody, That all sounds like good stuff and is similar to other work arounds I have had to learn dealing with drawings or models from others. Can you get the command that moves objects onto a new layer but keep the color, I have a lot of uses for that!Thanks,David David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188

You said that cleaning the file up after you imported it was slow.
Is the file still slow if you open it now, the way you sent it to me?
If not, can you send me the dwg file?

I see no problem here with the file running Rhino5 Windows on an oldish Macbook Pro laptop.

Can you tell me what version and SR of Rhino, Windows version, computer and graphics card & driver you have?
You can find the graphics card and driver stuff listed at Options->View->OpenGL


This is a Mac-only problem (bug) - in that in Windows Rhino you can’t have the individual object properties or command history in a separate non modal window. If the Mac is trying to display real-time updated object info for thousands of objects simultaneously, that’s just wrong, I think. There have been problems in the past with the non-modal properties panel slowing things down, but i think all that has been “optimized” on the Windows side of things,.


ok… thanks for the info… i’m kind of thinking this has been the culprit of at least one ‘mac rhino is unusable’ complaints.

Thanks Mitch,We can rule that out then, at least for my issues. The method of cleaning up and joining that Jody provided has helped considerably! Thanks! If anyone knows the command that will move objects to a layer yet keep other properties unchanged that would help immensely in the clean up process! Now if we can just get the engine manufactures to provide files cleaned up for installation drawings we would be in good shape! I don’t need the engine to run just want a simple drawing:) Thanks everyone for your help today!Best,David David & Kristen BuckleySV Sayonara(D) 843.735.9663
(K) 843.412.3188