Copy and scaling problems


I have been using the free version for some years for 3D modeling and recently I changed to Pro to obtain more features and better results.
The first part became true but other annoying issues appeared.

Copy / mirror an item:
I often need left and right versions of specific part, therefore I use the Copy/scaling (-1) functions to reverse the original design.
The original I always check for mistakes and export to STL, in order to check the quality of the design before I copy/scale.

Once I am satisfied with the result, I copy and reverse the part.
The result always contains mistakes c.q. the the design is not a solid and cannot be used for 3D printing.
Repairing the bad copies is extremely time consuming since the repair functions cannot manage.
On top of that, the sold inspector does NOT recognize the mistakes.

I can’t say which of the two functions creates these kind of problems since a straight copy is most of the time also incorrect.

This is a real downturn for me.

Does anyone have a solution?



First thing to check, You are using 2022 as your profile says?
This sounds like the bug in the exporter that was introduced a few versions back and then fixed. Anything mirrored failed in slicers when exported. I just tested on my windows 2022 version and scale -1 does work in my printer. However that may not be the case for Mac.

Basically you should be able to explode the mirrored version and regroup it and it will work, or download the earlier .stl exporter from the Extension Warehouse (the one made by sketchup) as this did work when the built in one didn’t.
It adds a new menu item to the File Menu, Export .stl rather than using the Normal Export option.
Try these options and see how it goes.
We’d be interested to know if this solves the problem for you because it tells us the bug still exists in Mac.


Yes, I am definitely using 2022 version.
I will try the other exporter.

I missed this on my first reading and was only thinking of the -1 bug, if a normal copy is causing problems there is something else going on. Perhaps it is a tiny face issue. How small and detailed are your parts? Can you attach one for us to look at.

My parts are sometimes pretty small but I always construct in oversize.
Minimum 10x bigger than the final size.
Scaling is done with the slicer.

I always check the copies with the solid inspector function.
Even when this is okay, the STL comes out with defects.

At the next occasion, I will share a file to inspect.

There is a known bug in the STL exporter in how it reverses the faces of flipped/mirrored components (SU-46202). I’ll bump it internally.


For the moment I am using the SimLab exporter.
Works good.

Does the old SketchUp STL export extension have the same problem? Or is that a suitable alternative for now?

What is the “old” exporter?
Before I used the 2017 in the free version and it had similar faults.
When we concerted SKP files in STL with Fusion 360, everything was okay.
It seems that these issues, at least with Mac, are not new.

This is the “old” STL exporter.
I still use it since I’m using SketchUp Make 2017 wich has no native STL exporter.
Never had any problems with it, allthough I cannot say for sure I have ever used it to export something “scaled to -1”. I mosly use flip along for mirroring…

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