Can I trust blender with object dimensions when importing printed-ready STL files?

I have imported this as .stl into Blender and I’ve made this measurement:

Can I trust it’s an accurate measurement? Didn’t print this yet but I feel that it’s a little bit small as I have similar real-life GoPro mounts just as that one and that distance there is standardized.

The units are specified by the stl-file mm, cm , m ,ft, in and ly ( yes lightyears). I see no reason why blender should change this. And if you know the distance… do they differ? (If not, why asking??)

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Since the STL is MM and you are working in MM, then as long as you have applied scale while building, things will be saved in the dimensions specified…and as long as you know about rounding errors which you seem to have taken care of adding the zeros after 13.5MM…I don’t know what material you will print with…so remember the shrinkage factor in some of them.


My experience has been that Blender is accurate as long as I have given it accurate information and that I’m looking at it with the right measurement setup.
Easier for checking, than asking millions, is to load it into a slicer to check the dimensions. When in the slicer, you can check, back and forth, to make sure the sizes are the same.
From there it is easy to dial in your shrinkage factor and the like.

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FYI, for anyone who works in Imperial inches like me: When I export STL from Blender with a scale of 1000, it is right on the money in Cura. If I export a mesh that is 2.105" in Blender, I can be confident that my digital caliper will read 2.105" of my print. Cura displays mm of my meshes (haven’t found way to change), but an inch to millimeter conversion confirms accuracy. Hope that helps any USA folks (anyone else who works in Inches) new to Blender > Cura > 3D Printer workflow.

Edit: I tend to print very small things, so I might have had to change to this method, to get them to import into Cura… either way, I just go with this and it works every time, no matter how big or small my prints are to be.

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This is crucial information but how do you know that? I’ve read here that the header description should have 6d 6d or mm written but I just can’t find that.

I’m currently using Cura as my slicer and as far as I could find it here and some other places, there is no way to measure .stl dimensions in Cura. As for asking the millions - let’s get real.

This is an older version of Cura (15.04.2)…it just works better with my printer and the addrrino controller…and as you can see when Dimensions are set in Blender and scale applied…it stays the same when imported to Cura… the only difference is the rounding in Cura…

Exactly, RSEhlers.
As to the millions, perhaps a bit of hyperbole. Smile, don’t take it so hard. A bit of levity helps the day go by.

FYI #2 - For a while I have been meaning to try out the 3MF file format, which I have read is supposed to be wonderful, and can include a bunch of crap that STL cannot. I just tried the 3MF Blender addon and exported to Cura… Not good. Scale was incorrect, and the mesh was a total effing mess. I think I will stick with STL for the time being (doing my scale 1000), and keep an eye out for 3MF improvements etc, and hopefully make it a part of my Blender > Cura > 3D Printer workflow in the future maybe, if it is indeed as kickass as they say. But man was that a bad first experience with the format.