I want to create parts for a 3D printer using OpenSCAD. Having some STL files from the vendor, but nothing else (no technical drawing, no CAD files).

Does anybody knows a free tool, that allows me to

  • measure distances between 2 selected vertices,
  • measure distances between a selected vertex and a plane defined by 3 vertices,
  • measure the radio of a circle defined by 3 selected vertices?

I very much like the way Blender allows to work with meshes, especially select vertices or planes, but unfortunately haven't found a way to measure with Blender.

  • 2
    $\begingroup$ As far as I know, there is no real size information saved in .stl files, only relative positions of points in a generic unit measure. When opening an STL-file, you will have to specify how long one "unit" is. Most editors probably use millimeters or inches by default, but mixing them up will yeild results such as this. Just thought you should know. :) $\endgroup$ Jan 2, 2017 at 11:21
  • $\begingroup$ At thingiverse, for example, you often find only STL files that print in the right size, so the values in the files seem to be mm. $\endgroup$
    – Thomas S.
    Jan 2, 2017 at 14:36
  • 3
    $\begingroup$ There is also a Blender community here on the Stack Exchange network if you have more general questions about Blender. $\endgroup$
    – tbm0115
    Jan 3, 2017 at 6:08

4 Answers 4


I suggest Blender. It's not the simplest of tools but it is free and learning it will improve your 3D printing skills. :-) (I write this answer also for future viewers of this question so I start basic).

Another answer can be found here, How do I measure a distance between two points?

  1. Import your STL file.
  2. Press the Home key to view everything.
  3. Select the model by clicking on it with your left mouse button. (Blender changed to left-click-select as of version 2.80)
  4. Hit tab to enter edit-mode.
  5. Press N (or use View | Properties) until the Properties panel shows up.
  6. Select the "Length" checkbox in the "Edge Info" section of the Properties panel (see image below).
  7. Select "Edge Select" mode (see image below)
  8. Select the edge to measure by clicking on it with your right mouse button.

Edge length

Screenshot of toolbar

If you need to measure the distance between to vertices with no edge. Create the edge by selecting them and pressing F. If you need to measure the distance between a vertex and any other point, select it and press E to extrude.


As @Gunslinger suggested, I would also recommend Blender for these tasks.

Blender comes with the Add-on "MeasureIt", which has to be activated manually in Edit ► Preferences ► Add-ons ► Official/Community ► search for MeasureIt, check the checkbox:

Blender preferences

Import your STL file via File ► Import ► STL ► ...

Select your object and hit TAB to enter Edit Mode and then follow the tips in this screenshot:



If you're running Windows, MS 3D Builder has a measuring tool and may already be installed on your machine.


Meshmixer has various measuring tools for STLs as well


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