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Using the 'To Sphere' Tool in Blender (Shift+Alt+S Guide for 4.x)

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    Sparrow Hawk
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Blender's "To Sphere" operator is a handy tool in Edit Mode that allows you to transform any selection of vertices, edges, or faces into a more spherical shape. It's a quick way to round out parts of your model or even create perfect spheres from arbitrary geometry. This guide will show you how to use it in Blender 4.x and newer versions.

What Does "To Sphere" Do?

The "To Sphere" tool works by taking the selected mesh elements and moving their vertices to conform to an imaginary spherical surface. It essentially averages the positions of the selected vertices relative to their median center point and then projects them onto a sphere. The strength of this effect can be controlled interactively.

How to Use the "To Sphere" Operator (Blender 4.x)

  1. Enter Edit Mode: Select your mesh object and press the Tab key to switch to Edit Mode.
  2. Select Geometry: Choose the vertices, edges, or faces you want to transform. This can be an entire mesh (select all with A), a linked part (select linked with L while hovering over a part), or any custom selection.
  3. Activate "To Sphere":
    • Hotkey: The most common way is to press Shift+Alt+S.
    • Menu: Alternatively, you can find it in the top menu under Mesh > Transform > To Sphere.
  4. Interactive Control:
    • After activating the tool, move your mouse cursor towards or away from the selection's median point. This interactively controls the Factor of the transformation, from 0 (no change) to 1 (a full sphere).
    • You can also type a numerical value for the factor directly (e.g., type 1 for a perfect sphere, 0.5 for a 50% spherical transformation) and then press Enter.
  5. Confirm: Click the left mouse button or press Enter to apply the transformation. You can cancel by right-clicking or pressing Esc.

(The linked video demonstrates the "To Sphere" tool in action.)

Practical Use Cases for "To Sphere"

  • Rounding Corners: Quickly make sharp corners or blocky parts of a model smoother and more rounded.
  • Creating Spherical Elements: Easily turn a selected part of a mesh, or even a primitive like a cube, into a perfect sphere. This is great for:
    • Modeling eyes for a character.
    • Creating planets or baubles.
    • Forming spherical joints or caps.
  • Base Shapes for Sculpting: Quickly generate a spherical base mesh to start sculpting from.
  • Abstract and Organic Modeling: Apply "To Sphere" to partial or complex selections to create interesting organic or abstract forms.
  • Correcting Deformations: If part of your mesh has been unintentionally flattened or distorted, "To Sphere" can sometimes help restore a more rounded volume.

Important Considerations

  • Sufficient Geometry: For the "To Sphere" tool to create a smooth spherical shape, especially from angular objects like the default cube, your selection needs enough vertices. Applying "To Sphere" to a basic 8-vertex cube will result in an octahedron-like shape (a sphere with very few faces). To get a smooth sphere from a cube, you'll typically want to subdivide it a few times (Right-click in Edit Mode > Subdivide) or add a Subdivision Surface modifier before using "To Sphere" (though applying the modifier first makes the change destructive).
  • Pivot Point: The transformation occurs around the median point of the selected elements.

Q: How do you turn a mesh selection into a sphere in Blender?

A: In Edit Mode, select the vertices/edges/faces you want to change. Then press Shift+Alt+S and move your mouse (or type 1 and Enter) to transform the selection into a sphere.

Q: What does Shift+Alt+S do in Blender?

A: Shift+Alt+S is the default hotkey in Blender's Edit Mode to activate the "To Sphere" transformation tool, which makes the current selection more spherical.

Q: Can I make only part of my mesh spherical using "To Sphere"?

A: Yes, absolutely. The "To Sphere" operator only affects the currently selected elements in Edit Mode. You can select any portion of your mesh – a few faces, an edge loop, or a complex island – and apply the transformation just to that part.

Q: Why does my cube not become a perfect sphere with "To Sphere"?

A: If you apply "To Sphere" to a default cube (which only has 8 vertices), it will look more like an octahedron. To get a smooth, round sphere, you need more geometry. Subdivide the cube a few times in Edit Mode before using "To Sphere," or use a Subdivision Surface modifier.