Solving CAD Design Problems with ChatGPT

In this brief tutorial we’ll discuss ways to incorporate ChatGPT into your design process using Tinkercad, to solve problems around the house.

What Is ChatGPT?

ChatGPT is a Large Language Model (a type of artificial intelligence) developed by OpenAI. It has been trained on extensive amounts of text from books, websites, articles, and other written sources. You can type questions and receive answers in human-like form. As of this writing, ChatGPT-3.5 is free, and ChatGPT-4 is a paid subscription [Editor’s Note: OpenAI released ChatGPT-4o for free in May 2024]. Your answers will vary from the ones I show here based on the version you use.

The help you’ll get depends on the prompts (questions) you ask. You need to be precise; as with an internet search, different questions get different responses. As of this writing, ChatGPT-3.5 hasn’t been trained on any data past January 2022, so it can’t help with more recent information [Editor’s Note: ChatGPT-4o pulls current information from the internet]. Its answers may be too brief or too involved for your liking, but as long as that answer contains the one nugget you need to work through your problem, it serves its purpose. Take from a ChatGPT conversation what works for you. Use what makes sense, figure out what doesn’t, or follow the generated instructions as a guide.

How can I use ChatGPT with Tinkercad?

Here are some ways you can incorporate this tool with Tinkercad:

• Brainstorming: Hold a discussion with it to produce ideas and solve problems.
• Instructions and Design Tips: It can tell you how to get started, how to use shapes, Group, and other tools, and how to make simple things. Some instructions may be unclear; it takes some prompting, and you might not get an answer that is satisfactory for you.
• Troubleshooting: It can help diagnose trouble and suggest potential solutions.
• Educational Resources: It can find online resources, tutorials, and communities that might help you.
• Research Assistance: It can find answers to questions, draft surveys, and questionnaires.
• Promotional Materials: It can create educational and informational content, and even images (with paid subscription). Again, figure out what makes sense and what doesn’t.

Project: Handle for mechanical bank lever

Above is a vintage coin bank. The problem: At one time the metal lever had a rubber handle, but that handle somehow disappeared, making the lever both unaesthetic and uncomfortable to use. Let’s make a replacement handle using the image below as a guide.

This is one iteration of ChatGPT instructions. Regenerating the question results in a different solution. I regenerated it several times, and often the solutions were too involved for my liking.

To make a barrel shape in Tinkercad, follow these steps:

1. Add the Base Cylinder:
   • Select the “Cylinder” shape from the basic shapes menu and drag it onto the workplane.
   • Adjust the height and diameter of the cylinder to fit the size of the barrel you want. This will be the central part of the barrel.
2. Create the Middle Bulge:
   • Duplicate the base cylinder by selecting it and pressing ‘CtrI+D’.
   • Increase the diameter of the duplicated cylinder slightly to create a bulge.
   • Reduce the height of this bulging cylinder so that it forms the middle part of the barrel.
   • Position the bulging cylinder in the center of the base cylinder.
3. Create the Tapered Ends:
   • Duplicate the base cylinder again and reduce its diameter slightly to create the tapered ends.
   • Reduce the height of the duplicated cylinder so that it forms one end of the barrel.
   • Position this smaller cylinder on top of the bulging middle part, aligning it with the center.
   • Duplicate this smaller cylinder and move the copy to the bottom of the bulging middle part, aligning it with the center.

But I did get some insight on how to easily make a barrel using a cylinder and torus:

Use a caliper to measure the lever’s thickness. It’s 1.98mm, so we’ll use 2mm to give room for clearance. We’ll make the handle 44mm×20mm×20mm.

Drag a cylinder into the workspace and stack a torus on it. Select them both, click the Align tool, and align their centers.

Select the torus and use the white middle grip to stretch it down over the cylinder. Use the conical grip to raise or lower it so it covers the cylinder properly. This will create a barrel shape.

Group the shapes. Click the Ruler onto it to access the text fields and type the desired dimensions. If you want to change the proportions, stretch the barrel; the grouped shapes will stretch as one.

Drag a tube into the workspace and resize it so that it’s half the height of the cylinder, but a slightly larger diameter. Click the Cruise tool, grab the white grip, and cruise it to the top of the cylinder.

Then click the Align tool and align their centers. Alternatively, just use Align directly. Group the two shapes.

Drag a box into the workspace, size it 2mm wide, make it a hole, and center with the Align tool. Make sure the box cuts deep enough into the handle to accommodate the bank’s metal lever. Then group the shapes.

This tutorial is excerpted from the new Make: book The Complete Guide to Tinkercad: Design, Sculpt, and 3D Print Your Ideas, available now at the Maker Shed and fine booksellers.