How to use artificial intelligence to design 3D-printed parts (without being fooled)

In 3D printing, printing is the easy part. The hard part, the one that takes hours, is design: turning a problem into a part that fits, holds up and can actually be printed. That is where artificial intelligence has saved me the most time. But AI is a copilot, not the pilot: if you don’t know what you’re asking for, it hands you something that looks great on screen and fails in your hand. At the “El futuro se imprime hoy” conference at ITESA (in Spanish) we talked about how AI is changing design. Here is the practical version.

1. To think the part through, before opening the design software

The first use, and the most underrated one, is simply talking it over. Describe to an AI assistant what the part has to do, where it goes, how much weight it holds and whether it will get sun or water. Then ask it for:

• two or three ways to solve it, with their pros and cons;
• the right material (PLA, PETG, ASA, TPU) and why;
• the list of measurements you need to take before designing;
• how to orient it on the printer so the layers don’t end up at the weak point.

In ten minutes you have a plan that used to take an afternoon of trial and error. That’s how parts like the mounts for satellite internet antennas we make at Cosmos begin: with the right questions.

2. To generate a first model

There are three routes, and they are good for different things:

Parametric code. Ask the AI to write the model in OpenSCAD, a free program that builds parts from code. For example: “a box of 80 × 50 × 30 mm with 2 mm walls, a snap-fit lid and two 4 mm screw holes”. The best part is that afterwards you change one number and the part adjusts itself. It works very well for boxes, brackets, spacers and clips.

Text to CAD. Tools like Zoo or AdamCAD generate simple mechanical parts and export them as STEP or STL. In a test by Xometry they did well with simple geometry and failed with complex parts: they are a good starting point, not a replacement for CAD.

Text or photo to 3D model. Generators like Meshy or Tripo create figures from a sentence or an image. They are great for characters, decoration or gifts, but they deliver a mesh without exact dimensions: they won’t do for a part that has to fit another one.

3. To improve the part

• Generative design: programs like Fusion let you mark where the part is held and what force it takes, and they propose lighter shapes that hold the same load. Less material, fewer printing hours.
• Review: upload a photo or a screenshot of the design to the AI and ask where it could break or which part will need supports. It isn’t always right, but it makes you look where you weren’t looking.

4. Where it still gets things wrong

1. Dimensions and tolerances. AI makes up numbers with great confidence. Measure with calipers and leave clearance on parts that fit together: 0.2 to 0.4 mm usually works, but it depends on your printer. Print a small test first.
2. Parts that carry weight or protect someone. There are no shortcuts there: calculations, real tests and the right material.
3. Copyright. Don’t copy protected designs or brand logos just because the AI generated them for you.
4. Good use. 3D printing is for solving problems: spare parts, mounts, tools, teaching materials. Never for weapons or for anything that puts someone at risk.

5. The workflow I recommend

1. Measure and write down what the part has to do.
2. Ask the AI for options, the material and a checklist.
3. Generate a base (OpenSCAD or text to CAD).
4. Finish it in design software: I use SolidWorks for anything with tolerances; Fusion, FreeCAD or Tinkercad work too.
5. Print a quick prototype, test it and adjust. It almost never comes out right the first time, and that’s fine.

Keep going

If you’re about to buy a printer, start with how to choose your first 3D printer, and to see what’s already being done in the country, 3D printing in the Dominican Republic. With Néstor Cortorreal (in Spanish) we saw how AI and 3D printing are already used together to make teeth. And if your school or company would like a talk about this, write to me.