Can't import STL files

I am 3D printing busts of my friends using photogrammetry. Great fun to produce these detailed models. I like Sketchup and have used it for some time for making models for model railways and I would like to use it for post processing 3D heads from STL files.
But, SU just hangs forever and never finishes. The files are large at 15Mb plus. Is this the problem?

Depends what you mean by Never, how long did you wait. I have had complex sculptural models, not as large as that take 24 hours to import.
It mostly depends on the complexity of the model and the speed of your computer.

Thanks for you prompt reply.
I must admit I have only waited a few hours and assumed SU had locked up. Windows 10 reports that SU is not responding so I assumed the worst. My PC is fairly fast on photogrammetry rendering. Roughly how long would I have to wait to import a 15Mb STL file?

There is no way to answer that.
It might be 1 minute after you crash out of it or another day.
As I said above it all depends on the complexity of the model, not necessarily the file size.
It can also be effected by how you import it.
Have you set the import options to the largest option, to avoid tiny face failure.
Have you turned off all extraneous Style options, like Profiles and endpoints, even turning off edges can help.

OK, I accept that, thank you.
But here is an oddity. I use Mesh Mixer to post process the STL files because I can’t as yet use SU even though that would be my first choice. Mesh Mixer loads my STL files of head scans in about 10 seconds!
How can Mesh Mixer achieve that when SU takes hours?
This is not a dig at SU, it is a respectful query.

No Idea.

if your using the ‘extension’ in an earlier SU version, then it will be using Ruby to process the file…

this can be very slow compared to ‘native’ processing used by SU v18, SU Web and Mesh Mixer…

your template, import units also make a difference…


Thanks for that John.
The reason that I would like to use SU to post process organic scans like a human head is because it is very good at creating abstract models. For instants, I would like to add a pedestal to a human head bust for which SU would be great.
But, I have found a work around. I can create the pedestal in SU, save it as an STL file, then import it into Mesh Mixer and join the two.
So, I have the best of both worlds. My happy experience and knowledge of SU lets me make the abstracts and Mesh Mixer lets me sculpt the organic models.
I tried to determine which version of STL import I have but failed.

Thanks for all your help. Cheers, Bruce

We could probably help you with that if we knew what version of SketchUp you are using. Please complete your profile.

OK, I have updated my profile.


So as @john_drivenupthewall mentioned, you are using the ruby version of the stl importer, so it is slower than the newer inbuilt stl importer built into 2018 and above.