Boolean Operations

Union

Merge two or more shapes into a single solid, with a sharp, blended or melded seam.

Union merges all selected objects into a single solid. Internal geometry at the intersection is removed; only the outer boundary of the combined shape remains.

Applying Union

Select two or more objects. You can use a lasso selection to pick multiple objects at once.
Click Union in the toolbar.

The merged result appears as a new part named Union. You can union more than two objects in a single operation.

Blend and Meld

A union normally joins two shapes with a sharp seam. Blend rounds that seam with a smooth fillet. Meld does what Blend does, and also bridges a gap between shapes that do not touch. Both are options of Union. Cut and Intersect do not have them.

Four unions: plain, blended, blended with a gap, and melded across the gap — Top: a plain union, and the same union blended. Bottom: two shapes that do not touch, blended and melded. Blend leaves the gap. Meld bridges it with a smooth neck.

Setting the Blend Mode

Select a union.
In the Value References panel, click Plain, Blend or Meld in the Blend row.

With Blend or Meld selected, a Blend Radius field appears. Its default is 1.0 in the current display unit. Type a value to change the size of the fillet.

Plain, Blend and Meld

Mode	What it does
Plain	Joins the shapes with a sharp seam
Blend	Rounds the seam with a fillet of the given radius. Shapes that do not touch stay apart
Meld	Rounds the seam, and joins the nearest areas of shapes that do not touch with smooth necks

Blend and Meld are volumetric operations. If the fillet looks coarse, raise the tessellation resolution. The Simplify setting does not affect them.