Where to Cut Your SketchUp Model into Parts for 3D Printing

By Aidan Chopra

When subdividing a SketchUp model into printable parts, start by thinking about what you’re going to do with the seams. If you’re going to sand, paint, and finish the model, then have at it and cut wherever you want. But sanding and finishing is a huge amount of work, especially if you’ve never done it before.

It’s much easier to make your cuts and seams look like they’re intentional parts of the model.

For a seam to look intentional, it has to work with the logic of the object. Every object has its own logic, an underlying order that informs how it’s shaped and structured. For example, here, the object is symmetrical left and right.

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A seam on the axis of symmetry is less objectionable than one that runs randomly in another direction. By following a line that’s already conceptually present in the object, the seam reinforces what the eye already perceives.

Another good place to hide a cut is at a change in elevation, curvature, or color. Placing a seam where the surface of a part is already interrupted or in transition will make it far less noticeable.

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This is the strategy most commonly employed for injection-molding parts. Pick up something around you that’s made of plastic and find the seams where the parts come together. If you can imitate that type of seam, people will readily accept that your object is a “real” thing.

It will feel correct among manufactured things in our injection-molded world, and you’ll fool people into thinking your 3D printed part came from a factory somewhere.

For very large constructions, the only option may be to establish a grid and cut into build-volume-size blocks. Sanding, finishing, and painting can work well on large parts, but expect to spend substantial time doing it right. If you’ve spent the energy to build a something that big, it’s worth the extra time to make it amazing.