What Does the Inflate Brush Do in Blender?

The Inflate brush in Blender is a fundamental Sculpt Mode tool designed to add volume to 3D models by pushing vertices outward along their surface normals. Unlike basic drawing brushes that add material in a single direction, the Inflate brush expands mesh surfaces omnidirectionally, making objects look puffed up or thicker. This guide breaks down how the Inflate brush works, its essential settings, and the best practical scenarios for using it in your digital sculpting workflow.

How the Inflate Brush Works

When you apply the Inflate brush to a mesh, Blender calculates the normal direction of each vertex within the brush radius and moves those vertices outward. This creates a rounded, ballooning effect that increases the local volume of your geometry while preserving the general contours of the model.

If you hold the Ctrl key while using the brush, it performs the inverse action—Deflate. Deflighting moves vertices inward along their normals, shrinking the volume and pulling the surface inward.

Key Settings for the Inflate Brush

To get the best results from the Inflate brush, you can tweak several key brush settings in the Tool Settings bar or N-panel:

  • Radius: Controls the size of the brush area. A larger radius affects a broader area of geometry, creating large structural volume, while a smaller radius allows for detail work like veins or folds.
  • Strength: Adjusts how aggressively the vertices move per stroke. Lower strength values (0.1 to 0.3) provide smoother, more controllable volume building.
  • Auto-Smooth: Applies minor smoothing to the vertices as they inflate, helping prevent the mesh from pinching or creating jagged geometry when heavily inflated.
  • Falloff: Determines how the brush strength tapers off from the center of the brush to its outer edge. A smooth falloff creates natural, soft inflation, while a sharper falloff creates distinct, punchy bumps.

Common Use Cases in 3D Sculpting

The Inflate brush is versatile and used across organic, stylized, and hard-surface sculpting:

  • Organic Modeling: Perfect for defining muscles, swelling soft tissue, puffing up lips, creating eyelids, or adding fat deposits on characters.
  • Cloth and Fabrics: Ideal for creating realistic seams, padded jackets, cushions, pillows, and buttoned tufts on furniture.
  • Fixing Thin Geometry: Useful for thickening areas of a sculpture that have become accidentally flattened or too thin during dynamic topology (Dyntopo) or remeshing operations.
  • Stylized Hair and Features: Great for forming thick, rounded locks of hair or cartoonish features that require clean, bulbous shapes.

Inflate Brush vs. Other Sculpting Brushes

  • Inflate vs. Draw: The Draw brush pushes geometry outward relative to the view or surface plane, whereas the Inflate brush pushes geometry outward in all surface directions simultaneously.
  • Inflate vs. Blob: The Blob brush creates spherical bulges on the surface, while the Inflate brush expands existing shapes uniformly without forcing a spherical contour.