<p>I am trying to print a model I designed in Blender on Shapeways.</p>

<p>The object has a hole in it:</p>

<p><a href="https://i.stack.imgur.com/iCaGP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/iCaGP.png" alt="enter image description here"></a></p>

<p>But when I upload it to Shapeways as a STL file, fixed the sizes, but the hole is filled up in the preview window for the object in Shapeways:</p>

<p><a href="https://i.stack.imgur.com/6P9iO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6P9iO.png" alt="enter image description here"></a></p>

<p>What could cause this? Will the model print properly?</p>

<p>(I cannot share the model here).</p>

[{'answer_id': 2785, 'author': 'Memnarch1113', 'author_id': 4241, 'author_profile': 'https://3dprinting.stackexchange.com/users/4241', 'pm_score': 2, 'selected': False, 'text': '<p>Double-check that your model is solid (i.e. watertight). Holes in the mesh, or (as other\'s mentioned in the comments) or problems with thickness can cause those issues. You can use <a href="https://netfabb.azurewebsites.net/" rel="nofollow">Netfabb\'s Cloud Services</a>, or download the free version of their app. There are other model repair services, too.</p>\n'}, {'answer_id': 2793, 'author': 'reemaj', 'author_id': 4257, 'author_profile': 'https://3dprinting.stackexchange.com/users/4257', 'pm_score': 1, 'selected': False, 'text': '<p>Just like the other already have mentioned, most likely your model has 3D printing errors. Either way, I would run it through a repairing service just to make sure it\'s free of 3D printing errors. I repair my models using this free automatic tool <a href="https://makeprintable.com/" rel="nofollow">https://makeprintable.com/</a> </p>\n'}]
['https://3dprinting.stackexchange.com/questions/2737', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/4099/']