3D printing (empty areas)


Hi. I have a problem with my project…I created a cube, in the middle I turned empty but when I export it and open with a sofware 3D print the software tells me is a solid block without any empty area.

How can I export without that problem? Or what I not doing right?

I use the push/pull to do the empty area and I export it in STL with a plugin for sketchup.


Make sure your faces are facing the correct direction.


Can I have a look at your file?


Have you got a wall thickness all the way round? Just trying to print a cube shell will slice as solid.


To illustrate what @jon1 meant, take a look at this image. Both objects are SketchUp "solid"s. The one on the left has no explicit wall thickness, so a 3D printer will think you meant it to be completely filled with material unless you tell the 3D printer otherwise (usually one of the printer software’s options). In the one on the right I have created an inner cube inside the outer shell. The printer software should understand that the space between these walls is “solid” and the inside is void.


Actually Steve, in that image the printer would see the second as a solid within a solid.
Face orientation tells it what is void.


Whoops, you are right! I forgot to reverse those faces. My bad! It should have looked like this:


The next problem you will have is printing something hollow without internal support, I am presume it is quite small.

And thanks @slbaumgartner for the image that is exactly what I meant :wink:

You could alternatively turn infill off on your slicer.


My cube:


From an image I can’t be sure what is going on at the bottom. It looks like a reversed face, but I can’t tell what else. Could you upload your model so we can check?


Upload your STL file so we can check it


Hi. There’s the Skp file:



Hi. Sorry, yesterday I had problems with post.

SKP file:




Looks like you have a few issues. On the bottom you have a hole in your model;

If you run Solid Inspector, you find out that you have a bunch of interior surfaces that you will need to delete out.


The surface Borders and Internal Face Edges need to be repaired by going into the model and deleting the geometry inside the model. The short edges are just an FYI letting you know that you have modeled geometry that is likely too small to print (next time you can probably model a curved edge with fewer segments and it will print just fine!)


It had non-manifold edges. mp_export.stl (40.7 KB)


Your fixed file is not fixed.


Thanks ppl! I’ll do better in next cube!