Erode

Erode shrinks a solid inward by the radius of a ball. Flat faces move inward. Inside corners become rounded, holes become larger, and thin features can disappear or split the part into separate pieces. All surviving pieces are kept.

An L-shaped solid after erode

How to Use

  1. Select a solid part
  2. Click Erode in the Reshape group of the toolbar
  3. Set Radius to the distance to shrink
  4. Wait for the operation to finish; use Cancel in the task area to keep the previous result

Parameters

  • Radius - The distance surfaces move inward (default: 1 mm). Must be greater than zero
  • Segments - The detail of the rounding ball (default: 12). More segments produce finer curves and take longer, especially on parts with pockets or notches

When It Refuses

The radius must be smaller than half the source bounding box’s smallest side. That is an upper bound, not a guarantee that the ball fits inside the shape. If no solid remains after erosion, the operation refuses the result and leaves the source visible. A thin feature disappearing is allowed as long as some solid remains.

Convex parts, such as boxes with no pockets or notches, use a fast exact erosion. Parts with inside corners take longer.

Tips

  • This changes the whole part’s dimensions. To round edges while broadly preserving the original dimensions, use one of the Round operations below
  • Radius is measured in the source part’s own coordinates. Non-uniform scaling applied afterward also stretches the rounding
  • These operations require a solid. Use Inflate Path to grow or shrink a 2D path