How to Change Curve Point Radius in Blender

Changing the radius of a specific curve point in Blender allows you to taper, thicken, or reshape individual sections of a curve object. This process is essential for creating organic shapes like vines, cables, or hair strands. By switching to Edit Mode, selecting a target control point, and adjusting its radius property using hotkeys or the Sidebar menu, you can quickly achieve precise control over your curve's thickness.

Method 1: Using the Alt + S Hotkey

  1. Select your curve object in the 3D Viewport.
  2. Press Tab to switch to Edit Mode.
  3. Select the specific control point you want to alter.
  4. Press Alt + S (the Scale Radius shortcut).
  5. Move your mouse to scale the point's radius interactively, or type a numerical value directly, then press Enter to confirm.

Method 2: Using the Sidebar (N-Panel)

  1. Select the curve object and press Tab to enter Edit Mode.
  2. Select the control point you wish to edit.
  3. Press N to open the Sidebar on the right side of the 3D Viewport.
  4. Click on the Item tab at the top of the Sidebar.
  5. Locate the Radius field under the Transform section.
  6. Click and drag the value slider, or click to enter an exact numerical radius value.

Visualizing Radius Changes

For radius adjustments to be visible in the 3D Viewport, your curve must have geometry or bevel thickness applied:

  1. Open the Object Data Properties tab (green curve icon) in the Properties panel on the right.
  2. Expand the Geometry section.
  3. Under Bevel, increase the Depth value (or assign a custom object/profile).

Once a bevel depth is applied, changing the radius of any control point will instantly scale the thickness of the curve mesh at that location.