Adjust the brush size while proportional editing is active

In Blender, you control the size of your proportional editing brush using the scroll wheel or by pressing F and then moving your mouse. The brush size determines how large an area around your selected vertex or edge gets affected when you move it. A smaller brush affects only nearby geometry; a larger brush pulls in more distant vertices smoothly.

The fastest method during editing is to scroll your mouse wheel up to increase the brush size or down to decrease it. You'll see a circle outline on your mesh showing the current brush radius in real time. This circle grows or shrinks as you scroll, and the change takes effect when ready.

If your mouse doesn't have a scroll wheel or scrolling feels imprecise, use the F key instead. Press F, then move your mouse away from or toward your original cursor position. Moving the mouse outward enlarges the brush; moving it inward shrinks it. Press left-click or Enter to confirm the new size.

Key Takeaways

  • Scroll your mouse wheel up or down while proportional editing is active to change the brush size when ready without interrupting your workflow.
  • Press F and move your mouse to adjust brush size if you prefer keyboard-and-mouse input over scrolling.
  • The circle outline on your mesh shows the exact brush radius, so you can see the affected area before you move geometry.
  • Brush size changes persist until you manually adjust it again, so you can work at the same scale across multiple edits.

Using the scroll wheel for quick adjustments

The scroll wheel is the most direct way to change brush size because it requires no key presses and works while you're already moving geometry. Start by activating proportional editing (press O), select a vertex or edge, and begin moving it with G. While the move operation is active, scroll up to expand the brush or scroll down to shrink it.

Watch the circle outline as you scroll. The outline expands or contracts in real time, showing you exactly how much geometry will be affected. This visual feedback helps you dial in the right size before you release the mouse button and confirm the move. If the brush is too large and pulling in unwanted geometry, scroll down when ready. If it's too small and not affecting enough area, scroll up.

One common mistake is scrolling too much in one direction. Small scroll movements change the size incrementally, so you can fine-tune the radius without overshooting. If you scroll and the size jumps too far, scroll in the opposite direction to back up.

Using the F key for precise control

The F key method gives you more deliberate control and works well if you want to set a specific brush size before you start moving geometry. Press F while proportional editing is active. Your cursor will change, and a circle will appear on your mesh showing the current brush radius.

Move your mouse away from the center point to enlarge the brush or toward the center to shrink it. The circle grows and shrinks as you move, giving you a clear visual of the new size. Once the circle is the size you want, click the left mouse button or press Enter to confirm. The brush size is now set and ready for your next move operation.

This method is useful when you're switching between detailed work (small brush) and broad adjustments (large brush). You can set the size once and then perform multiple moves without needing to adjust again.

Understanding the falloff curve and how it affects brush behavior

Blender's proportional editing uses a falloff curve that determines how strongly vertices are affected based on their distance from the center of the brush. The falloff is separate from the brush size—the size controls the outer radius, while the falloff controls how the influence decreases from the center outward.

By default, Blender uses a smooth falloff that tapers influence gradually. You can change the falloff type by pressing Shift+O while proportional editing is active, or by looking in the Tool Options panel on the left side of the 3D viewport. Common falloff types include Linear (sharp transition), Smooth (gradual curve), Sphere (rounded), and Root (steep falloff near the edge).

The falloff type doesn't change the brush size itself, but it changes how the size feels in practice. A Linear falloff with a large brush can feel harsh because vertices at the edge are pulled almost as much as vertices at the center. A Smooth falloff with the same brush size feels gentler because influence drops off more gradually. Experiment with different falloff types to find what works best for your modeling style.

Checking and resetting brush size in the properties panel

If you want to see your current brush size as a number rather than just a circle, look at the Tool Options panel on the left side of the 3D viewport. When proportional editing is active, you'll see a field labeled Radius or Size showing the brush radius in Blender units. You can click this field and type a specific number to set the brush to an exact size.

This is useful when you need to match a brush size across multiple edits or when you want to return to a size you've used before. For example, if you know you want a radius of 2.5 units, you can type that number directly instead of scrolling or using F to estimate.

To reset the brush to a default size, you can delete the current value and type a new one, or you can press Backspace while the field is selected to restore the default. Different Blender versions may label this field slightly differently, but it's always in the Tool Options panel when proportional editing is active.

Common mistakes and how to avoid them

The most frequent mistake is forgetting that proportional editing is still active after you finish an edit. If you move a vertex and notice that unrelated geometry is moving too, proportional editing is probably on. Press O to toggle it off, or check the header of the 3D viewport—it will show "Proportional Editing: ON" if it's active.

Another common issue is setting the brush size too large for detailed work. If you're trying to make a small, precise adjustment and the brush pulls in too much surrounding geometry, scroll down to shrink the brush significantly. A brush that's too large can undo fine details you've already created.

Some users also confuse brush size with falloff type. If your edits feel too soft or too harsh, the problem is usually the falloff curve, not the size. Try changing the falloff type (Shift+O) before you assume the brush size is wrong. A smaller brush with the right falloff often works better than a large brush with the wrong falloff.

Frequently Asked Questions

Can I change the brush size while I'm moving geometry?

Yes. Press G to start moving, then scroll your mouse wheel or press F to adjust the brush size. The move operation stays active, and the brush size changes in real time. This lets you fine-tune the affected area without releasing and restarting the move.

What's the difference between brush size and falloff?

Brush size is the outer radius of the circle—how far from the center the effect reaches. Falloff is how the influence decreases from the center to the edge. A large brush with Linear falloff pulls vertices at the edge almost as much as at the center. A large brush with Smooth falloff pulls them much less. Change falloff with Shift+O.

Why does my brush size keep resetting?

Blender remembers your brush size between edits, but some operations or tool switches can reset it. If you switch to a different tool and back, the size may return to default. You can also check the Tool Options panel to see if a preset is overriding your size, or manually set the Radius field to your preferred value.

Is there a maximum or minimum brush size?

Blender doesn't enforce a hard limit, but very large brushes (larger than your entire model) become impractical, and very small brushes (smaller than a single vertex) don't affect anything. Most work happens with brushes between 0.5 and 10 Blender units, depending on your model's scale.

Can I use proportional editing with multiple selected vertices?

Yes. Select multiple vertices, press O to set up proportional editing, then press G and move. All selected vertices move together, and the brush size controls how much surrounding geometry is pulled along. This is useful for moving entire sections of a mesh while keeping the shape smooth.