How do you make .obj or .skp objects solid for 3d printing

[PhilH]

I am working on a project for a family member, basically making resin printed models of Russian and NATO military assets as training aids. Most are readily available on the internet as .stl files ready for printing but some are .obj or .skp files which are basically just shells not suitable to be imported or converted into print ready files.

 

So take a helicopter fuselage. If the original file was produced in Sketchup say then it is a basic hollow shell which at the size I need to print them at makes them incredibly fragile. I would like to know if there is a way of making this file into a solid object which can be converted into a .stl file for a successful print without breaking the bank. I did try meshmixer as I was told you could do it in that but I couldn’t seem to do it in the basic (free) version.

 

Any advice on this would be appreciated.

Edited March 12, 2023 by PhilH

[monkeysarefun]

IF the helicopter fuselage has no holes for windows etc (ie the windows are filled in as part of the mesh) so it creates an enclosed object similar to say an unbroken chocolate easter bunny then it should print ok. If there are minor holes then meshmixer should work.  The workflow is :

 

Import the .obj file into meshmixer.

 

Select the analysis icon on the left hand side.

 

Click on Inspector. This will highlight all the holes in the mesh. There should be a menu that has popped up that has "auto-repair all" which will attempt to fill holes. 

 

Alternatively SketchUp has a free extension called Solid Inspector 2. This is invaluable for locating issues such as holes, random faces etc, though it only highlights them, you need to manually fix them, I use this a lot.

 

If you are up for Blender, it too has an add-on called 3D print or something. This has a "make manifold" option that will attempt to fill holes..

[PhilH]

5 hours ago, monkeysarefun said:

IF the helicopter fuselage has no holes for windows etc (ie the windows are filled in as part of the mesh) so it creates an enclosed object similar to say an unbroken chocolate easter bunny then it should print ok. If there are minor holes then meshmixer should work.  The workflow is :

 

Import the .obj file into meshmixer.

 

Select the analysis icon on the left hand side.

 

Click on Inspector. This will highlight all the holes in the mesh. There should be a menu that has popped up that has "auto-repair all" which will attempt to fill holes. 

 

Alternatively SketchUp has a free extension called Solid Inspector 2. This is invaluable for locating issues such as holes, random faces etc, though it only highlights them, you need to manually fix them, I use this a lot.

 

If you are up for Blender, it too has an add-on called 3D print or something. This has a "make manifold" option that will attempt to fill holes..

Thank you. More investigation/ effort needed on my part methinks.