Splitting a model: how to cut a big part into pieces

When to split a model

The most common reason is size. The largest part we can print in one go is 246 × 246 × 256 mm, which is the build volume of our printers. A bigger object, such as a helmet or a large decoration, has to be split. The second reason is shape: two halves laid on the bed by their cut face print without supports and with a better surface than a single part with overhangs.

Splitting can also change the orientation. Long thin objects, such as a rod, bend or break along the layers if they are printed standing, and last longer if they are split and laid flat.

Where and how to cut

Make the cut where it will not be seen, for example along an edge or in a groove, or where the part is not under tension. A flat cut plane is the simplest and glues well. Joints built into the model help too:

• Pins and holes. One part has a pin, the other a hole with 0.2 to 0.3 mm clearance. The parts do not shift while gluing.
• A dovetail lock or a tongue and groove on long straight cuts.
• A larger glue area. A slanted cut gives more area than a straight one and a stronger joint. More on gluing in the entry on gluing prints.

What we do and do not do

We do not split the model for you or glue it. You do the split in a program such as Blender, Fusion or Meshmixer and save each part separately, or all in one file. You set the quantity in the order. The printed parts arrive separately and you join them at home with glue.

The price is calculated from the real print of each part, so you see what the set costs. Several small parts fit better on one bed, which reduces time and the price per piece. Splitting into smaller parts can therefore come out cheaper than one big piece.

What to watch for

Allow for shrinkage and clearance, so that pins and holes fit. With bigger parts make sure the layers run in the same direction in both halves. And one more thing: a joint will always be weaker than a solid part, so do not put it where the load is greatest.