What a torus radius is and where to find it

A torus in Blender is a doughnut-shaped 3D object. It has two measurements that control its shape: the major radius (how far the doughnut's tube extends from the center) and the minor radius (how thick the tube itself is). When you change either radius, the whole shape gets bigger or smaller in that direction.

When you first add a torus to your scene, Blender gives it default sizes. You change these sizes in the properties panel on the right side of the screen, or by typing exact numbers into the tool options that appear when you first create the torus. The radius values are measured in Blender units, which are arbitrary — they just set the proportions relative to everything else in your scene.

Key Takeaways

  • A torus has a major radius (the distance from the center to the middle of the tube) and a minor radius (the thickness of the tube itself).
  • You can change both radii when ready after creating the torus by typing numbers into the tool options at the bottom left of the 3D viewport.
  • If you create the torus first and then want to change it, you must enter Edit Mode and scale the geometry, or delete it and create a new one with the correct measurements.
  • The quickest method is to set the radii right when you add the torus, before you do anything else.

Adding a torus with specific radii from the start

The easiest way to get a torus with the exact radii you want is to set them before you finish creating it. Start by pressing Shift + A to open the Add menu, then navigate to Mesh and select Torus. A torus appears in your scene with default sizes.

Before you click anywhere else or press any other key, look at the bottom left corner of the 3D viewport. You will see a panel labeled "Add Torus" with two fields: Major Radius and Minor Radius. Click into the Major Radius field and type the number you want — for example, 2 for a larger doughnut hole. Press Tab to move to the Minor Radius field and type the thickness you want, such as 0.5 for a thin tube. Press Enter to confirm.

If you miss this window or it closes, you can undo the torus (Ctrl + Z), delete it, and add a new one. The tool options only stay open for a few seconds after you create the object, so speed matters here.

Changing radii after the torus is already in your scene

If you created a torus and now want different radii, you have two practical options. The first is to delete the torus and add a new one with the correct measurements — this is the cleanest approach if you have not yet built anything around it.

The second option is to scale the torus using the Scale tool. Select the torus, press S to enter Scale mode, then type a number and press Enter. Typing 1.5 makes it 50 percent larger in all directions. However, this scales both the major and minor radius equally, so you cannot change one without changing the other. If you need to adjust only the major radius or only the minor radius independently, scaling will not work — you would need to enter Edit Mode and manually adjust the vertices, which is more complex.

For most situations, it is faster to delete and recreate the torus than to try to fix it after the fact.

Understanding major radius versus minor radius

The major radius controls how wide the overall doughnut is — the distance from the very center of the torus to the middle of the tube. If you increase the major radius, the doughnut gets wider and the hole in the middle gets bigger. If you decrease it, the doughnut shrinks and the hole closes up.

The minor radius controls how thick the tube is. A small minor radius makes a thin, delicate doughnut. A large minor radius makes a fat, chunky one. Changing the minor radius does not affect the size of the hole — only how much material makes up the ring itself.

In Blender's Add Torus panel, you will see both fields clearly labeled. The default major radius is usually around 1, and the default minor radius is usually around 0.25, which creates a typical doughnut shape. Adjust these numbers based on what your scene needs.

Using the properties panel to check or modify radii

After you create a torus, you can see its current radii in the properties panel on the right side of the screen. Look for the Object Data Properties tab — it looks like a green triangle. Scroll down until you see Major Radius and Minor Radius listed with their current values.

You can click on these fields and type new numbers to change them, but this approach has a limitation: it stretches or squashes the geometry rather than regenerating the torus shape properly. The result may look distorted. For this reason, it is better to delete the torus and create a new one with the correct radii than to edit these values after creation.

Common mistakes when working with torus radii

The most common mistake is waiting too long to set the radii. If you create a torus and then add materials, modifiers, or other objects around it, you lose the chance to use the tool options. At that point, changing the radii becomes much more work.

Another mistake is confusing the Scale tool with radius adjustment. Pressing S and typing a number scales the entire object uniformly, which is not the same as changing the major or minor radius independently. If you need precise control over one radius only, scaling will not give it to you.

A third mistake is trying to edit the radii in the properties panel and expecting the torus to reshape itself. Blender will change the values, but the geometry stays the same, creating a mismatched appearance. Always regenerate the torus instead.

Frequently Asked Questions

Can I change just the major radius without changing the minor radius?

Not after the torus is created. You must delete it and add a new one with the correct major radius while keeping the minor radius the same. The Scale tool affects both equally, so it cannot isolate one radius.

What happens if I scale a torus after I create it?

Scaling makes the entire torus larger or smaller uniformly. Both the major and minor radii increase or decrease by the same percentage. If you scale by 2, a torus with major radius 1 and minor radius 0.25 becomes major radius 2 and minor radius 0.5.

Where do I type the radius numbers if the tool options panel is gone?

If you closed the tool options, delete the torus and create a new one. The panel appears automatically when you add a torus and stays open for a few seconds. You can also press F9 when ready after creating the torus to bring the panel back if it closed.

Can I make a torus with a very small major radius?

Yes, but if the major radius becomes smaller than the minor radius, the torus will intersect itself and look like a sphere with a pinched middle rather than a doughnut. This is mathematically valid but usually not what you want visually.