Whenever you create a model in 3D, the inside is automatically filled in by the 3D modeling program. Of course, it is perfectly possible to 3D print a solid model, but the cost involved will rise dramatically due to all the extra material needed to print the whole model. It is also rather wasteful; your model will look the same whether it is hollow or solid, but using all that excess material is less economic or energy-efficient and therefore has a more negative impact on the environment.

That’s why we bring to you the Hollowing Tool!

The Hollowing Tool automatically hollows out the inside of your model, leaving only the optimal wall thickness behind for printing. Your model will look exactly the same, but it will be lighter, cheaper and better for the environment; and therefore have the added benefit of making you feel good about yourself too.

The principal benefit of the hollowing tool is that it significantly reduces the cost of printing. Firstly, it reduces the amount of material used, and your item will also be lighter, making it cheaper to ship. As there is less to print, this also means that the build time of your model will be reduced, which also reduces the price and makes sure you get your model faster! Finally, printing a solid model in 3D can also cause internal stress in the object due to heat building up during the printing. The material you use can also be a factor: in certain materials used for 3D Printing, the surface of the object can actually warp if not hollowed out. Also, for a material such as ceramics, it is impossible to print without making the object hollow.

Hollowing a 3D model by hand is a tricky and time-consuming process, which is why we’ve introduced the Hollowing Tool on the Materialise Cloud. It is easy to integrate and even easier to use; all you need to do is input the minimum wall thickness your model needs, and the tool takes it from there, saving you time and money.

There are a few things to keep in mind before implementing this tool:

  • Don’t forget to take into account the material you are printing with! Certain materials require thicker walls (for example, ceramic needs much thicker walls than stainless steel or titanium), and therefore the hollowing tool will need to be used in tandem with the Wall Thickness Analyzer – walls that are too thin can lead to fragile prints that could even break during shipment. Hollowing your model does mean that your object will be less sturdy than if it was solid, but this can be countered by raising the minimum wall thickness. You may also need to add a base to enable your model to stand, if it is top-heavy or oddly proportioned.
  • The file will also become heavier due to the added number of polygons in your mesh, but you can combat this by making the inside of your model less detailed than the outside! Also be sure to check whether the surface normals of your model are facing the right direction. The normals on the exterior should be facing outwards, and those on the interior should be facing inwards. Normals facing the wrong direction should come up as a hole in the mesh of your model.
  • Don’t forget to add escape holes: these are essential in certain types of 3D Printing. Unless you want your model to be filled with powder or resin, don’t forget to design some escape holes into the model so the excess material can drain properly. We recommend designing at least a minimum of two.

Although hollowing your model is not essential, it is definitely the most economical and efficient way to 3D print your designs. And with the Hollowing Tool, the process is entirely automated, sparing you the fiddly process of hollowing out the model yourself.