I've set my Units (in scene properties) to Metric, and the Scene Scale to 0.01 hoping to get the Blender dimensions it mm's. While the (normal) scale is 1 for x,y,z, the standard cube has the dimensions 2x2x2 cm. When I export this to an STL and open it in a slicing program (Netfabb, Slic3r or Cura) they all give the dimensions: 2x2x2 mm. While exporting, the scale is 1.

What am I doing wrong? I hope you can help me.



The STL exporter doesn't take Scene Scale into account. Import your STL back into Blender (it will have the same size) and drag Scene Scale up back to 1.0, and you'll see how the cube grows relative to the grid.

1 Blender unit equals 1m, but STL seems to assume 1 unit as 1cm.

If you want 1 unit to be 1mm, set Scale on STL export to 0.1 and
Scene Scale to 0.001 to make it match the output scale in viewport.

Note that the STL will be 10x smaller if you re-import it into Blender!

  • 2
    $\begingroup$ Hi CoDEmanX, I found that STL does not use units, it is up to the interpretating side which units are used. In my case Cura and Netfabb use mm, therefore the STL "has" mm as unit. This would explain why I always see the same size (unitless). $\endgroup$ – Rogier Mar 5 '14 at 16:54

Shortly after I posted the question, I got some help in real life (I did not know that was also a possiblity :) )

Apparently, STL's do not have a unit. However, the program interpretating the STL gives it units. In my case Cura and Netfabb both interpretate my STL as mm. This would explain why I always saw the same size (unitless). Because of this, I should also create models in mm's, so I do not have to worry about Scale on STL export.

I want answer my own question to give some more explanation. I am not using the Scale on STL export, but I am using the scene scale. By setting the scene scale to 0.001, I can really make my model in mm's; in the properties menu I only have to think about mm's. With these settings I am able to export my model as a STL, and see it correctly in Netfabb or Cura.

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    $\begingroup$ Scaling my model up by 1000 while exporting worked. My units were in centimeters. Here's a link with pictures of what I did: imgur.com/WggbP4N $\endgroup$ – Greg May 19 '16 at 11:16
  • $\begingroup$ yep, no matter if you change the scale soon (design) or later (export), just remember to do it 0.001 for mm, if the mesh is shown as m (default Blender i guess). Case that you need model in cm but printing in mm, you can play both values... so it's just perfect. $\endgroup$ – erm3nda Sep 6 '16 at 11:37
  • $\begingroup$ Why would a 3D-printing format not have units? $\endgroup$ – Kyle Delaney Jun 16 at 4:53

Set Blender in metric mode. Don't touch the scene scale. When export to .stl set the scale to 1000 (in the export menu). It seems that most slicer use mm. :)

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    $\begingroup$ Could you please elaborate on how to do this? If the OP (or anyone else reading this answer) doesn't know how to change the units or set the scale this answer is useless to them. $\endgroup$ – PGmath Apr 3 '16 at 20:43
  • $\begingroup$ That's the shortest workflow to do it, totally yes, don't touch then set scale on the exporting step. $\endgroup$ – erm3nda Sep 6 '16 at 11:38

I had the same question, but my measurements are in inches, and I'm trying to print something to fit something inside of a drawer, so everything was measured in inches. (I probably could have redone all the measurements in mm or converted them, but :shrug: ).

Anyway, I was able to keep all the dimensions the same and build the widget using inches (pic 1) and then export the .stl by setting the Scale value in the export box to 25.40 which is mm/inch (pic2).


I am on Blender 2.79b.

Quick Edit: I also found this helpful documentation page on the subject


I have found a fool proof way to make a 5mm cube, and for me to be able to import it into my slicing software (PrusaSlicer based on Slic3r) and it prints a 5mm cube without need for any alterations.

Just to clarify I'm using Blender 2.79, Go to "Scene" (a few left of the modifier tab) Change Units from "Unit Presets" to "Millimeters" When you go to File-Export-Stl Set the scale (bottom left) to 0.5 and you should be good to go!


to getting right dimensions, set unit system : metric scale : 0.001

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