How to prepare model for 3D printing

We all know that 3D printing is either here or at least just around the corner. But there’s more to 3D printing a model than just slapping some meshes together and calling it a day. You have to prepare your model to be 3D-printing ready, and we are going to tell you how to do it.

The first step ideally happens even before you open your 3D modeling software. You should consider the material you are going to print it in, as well as the technology used for the printing. Can you have interlocking parts? Do you need escape holes for support material? Can the material and the process support all the shapes and the level of sharpness that you need? You must think about it before you model, and check out the printing and material guides online. 3D printing vendors want you to succeed and usually provide clear and exhaustive detail on what certain materials and methods can or can’t do.

While modeling, you should also consider the center of gravity, because you don’t want your model to topple over or require supports. You should also be mindful of any small and intricate details - materials and printing processes have their limitations and some of those limitations affect the level of detail.

Think about the size of the object. Printers have their minimum and maximum bounding boxes, and those have to be taken in consideration. Certain materials have issues, too, as they shrink during the production. Design with these tolerances in mind. Or, if it’s too late for that, fix it in your software.

You should also make sure that all the shells, all the parts of your model connect. 3D printing companies are more than ready to charge you for the amount of parts on your model, so make sure that turrets stay on the tanks (or are connected to it by the sprue), hair connects seamlessly to the cat and so on.

You might also want to check your model for any ngons - anything with over 4 sides or 4 vertices is considered an ngon. Those should be corrected and reduced to quads and triangles, as printing software finds those more palatable.

Now that you have a model, you should take care of its thickness - which is important in software that’s not primarily designed for 3D printing. Blender, Maya and others make models with walls so thin as to be unprintable. Now, it wouldn’t really matter that much if you were printing the object as a lump. The tricky part is that you want to hollow out your out because many 3D printing companies price it on mass. Holes are needed for the support material to pour out and save you money. And that’s why you suddenly need thicker inner walls. Luckily for you, your software usually has tools which can increase thickness automatically, with variable result

s. Except that it leads to fun new adventures like hunting for non manifold geometry, which means edges that are connected to more than two faces, overlapping faces and other modelling relics that won’t print well. While you’re at it, check out for any stray faces created in the geometry while you were applying thickness to the model. You should also look for holes, because the models should be generally water-tightOh, and look for inverted normals: the appear normal in your modeling software, but the printer will leave holes.

However, automatic thickness might not provide all of the thickness that your material or printing process requires, so you have to charge in once more, making suspect parts thicker. The good thing is that some websites like Shapeways let you upload the model and then they show you any possible issues with wall thickness or loose shells (not with holes, though - they have no way of distinguishing a hole that’s been designed from a hole that’s random).

The last and the easiest step is making sure you export the model in the right format. It all depends on the printing software in use by you or your printing vendor. Again, this information isn’t hard to find and modeling softwares usually have many options for export.

Or you can just say “screw it all”, and buy 3D printing models on a website like CGTrader.With 19,000 3D printing-ready models on site, they will have anything you need. And with 5,000 of those models being free, it might be cheaper than doing it yourself, too!

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