Importing, exporting and making ‘manifold’ objects in sketchup

In a nut shell:

An importer and exporter plugin for STL files in sketchup, along with a program to make your objects ‘mainfold’ can be found in one file here or here (mirror). Read the ‘how to’ text file in the zip.


In order to import an STL model, such as those from thingiverse, into sketchup you will need to use a plugin. A quality free plug-in that does just this task can be found here.

Unfortunately it isn’t quite perfect. For example, when you load a STL file in blender its shown as a clean model.

A mendel STL file shown in blender

However, when that same STL file is loaded into sketchup it it looks like this.

The same mendel STL file in sketchup

As far as I can tell there is no change the geometry of the object, as can be seen when you turn off edges making them invisible. Below is the same file with no changes made other than to turn edges invisible. This was done by going to wire frame mode (view-> face style -> wireframe) , draging a box around the object to select the edges and using the context menu to select ‘hide’. Then return to shaded view. To view hidden lines select view->hidden geometry from the tool-bar.

The same STL file with view edges made invisible.

The object also appears normal if exported using this plug-in and is again viewed in blender. Although, the dimensions of the object may have changed. Either that or the perspective has changed and I’m not knowledgeable enough to work out which.

Before exporting your own objects made in sketchup for use on a reprap, be sure to give it a once over with a fantastic plugin called Manifold 2.2. It does the following:

Looks at the contents of a selected group and tries to fix it so it is ‘manifold’ for 3D-printing etc.

The group needs to be a 3D shape which is fully surfaced without internal divisions or intraneous/extraneous geometry/entities…

When run…

It removes ‘non-face/non-edge’ entities.
It removes ‘disconnected geometry’.
It removes ‘unfaced-edges’.
It runs an initial ‘health-check’ and reports.
It removes face ‘flaps’.
It heals ‘holes’.
It removes ‘internal faces’.
It orients all faces consistently to face ‘outwards’.
It erases ‘coplanar edges’ [optional].
It ‘triangulates’ all of the faces [optional].
It highlights major errors.

By doing this along with some other requirements objects you make in sketchup may be printable on some level. Not having my own mendel I cant put this to the test just yet. So if you see something here that doesnt seem right, by all means let me know.

Again, each of these files can be found in one package with a short ‘how to’ here and here(mirror).

As always, if you find your self using this plugins on a daily bases or for a commercial application, make sure you send a donation in the direction of the creators.

About Richard

I am a Materials Engineering working in the field of Magnetic Materials in Melbourne, Australia. This blog covers my personal interest in all things CNC.
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6 Responses to Importing, exporting and making ‘manifold’ objects in sketchup

  1. Allan E. says:

    If you download ReplicatorG these days, it comes with an integrated version of Skeinforge. If Skeinforge can run without barfing, odds are you’ll get something out of your Mendel when you get it running.

    Of course, if you break the 45 degree rule, it might not print very NICELY…

    • Richard says:

      I haven’t had a chance to take a look at ReplicatorG just yet, but its high up on my ‘to do’ list.

      When I do get around to using it I will do some testing to see how it handles sketchup files that have been imported from different formats. Should be interesting to see.

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  4. Glenn says:

    Just as an FYI the stl importer you link to is supposed to import binary and ascii stl files but I could only get it to work with ascii stl’s and even then they had to be simple shapes or the files were too big and crashed SketchUp (SK7 Pro under Win 7).

  5. Pingback: Making objects ready to 3D print – 3D Printer Assembly Instructions How-To's Slicers and Videos

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