Chisel

Blending fillets the seam where two SDF expressions meet: booleans, mirrors, arrays, emboss/engrave. Set the radius on the modifier and the join becomes a smooth fillet without any extra geometry.

Smooth blend

Where blending lives

ModifierSettingRange
BooleanBlend Radius0.0–10.0, soft max 2.0
CarveOuter (with the Blend toggle)soft max 2.0
BisectBlend, plus Corner Blend per polyline planesoft max 2.0
MirrorMirror Blend0.0–2.0, soft max 0.5
Array (Line / Circle)Smooth0.0–2.0, soft max 0.5
Emboss / EngraveBlend Radius (outer) and Inner Radius (inner)0.0–10.0
SmoothRadius: a floor for every join abovesoft max 2.0

Boolean blend

The most common use of blending. Set the Blend Radius on a Boolean modifier and the seam between the two operands becomes a smooth fillet, including across Difference, Union, Intersect, and Slice.

  • Blend Radius: fillet radius
  • Blend Profile: Round / Sharp / Soft / Tight / Chamfer (see Profiles)
  • Blend Smooth (Chamfer only): softens the chamfer’s edges
  • Material Blend: width multiplier for the color seam, independent of the geometry blend (see Profiles)

Mirror blend

Push Mirror Blend above zero to fillet the join across the mirror plane. Useful when modeling symmetric objects where you don’t want a sharp central seam.

Array blend

Both Linear and Circular Array have a Smooth parameter that fillets the join between adjacent copies. Pair it with a small Count and you get continuous flowing forms; pair it with a large Count and you get rippled surfaces.

Carve and bisect blends

A Carve blends its edge exactly like a boolean (Blend toggle, Outer radius, Profile, chamfer Smooth) and its target answers to Ctrl + B and the blend arc like any boolean target. A Bisect blends its cut edge with the same controls, and every corner of a polyline fence has its own Corner Blend. Both have viewport handles: the orange ring around the bisect arrow drags the edge blend, the orange corner dots drag each corner.

Global smooth

The Smooth modifier sets one radius for every join in the chain at once. It is a floor: any seam sharper than the radius rounds up to it, any seam you already blended wider keeps its value, unless you tick Override All.

Emboss / Engrave: dual blends

Emboss and Engrave have two independent blend radii:

  • Blend Radius (outer): where the stamp meets the host surface
  • Inner Radius (inner): the corner of the embossed feature itself

Set them to different values and profiles for sharp logos with soft outer transitions, or smooth recesses with sharp inner edges.

Workflow

  1. Add the modifier (Boolean, Mirror, Array, Emboss).
  2. Locate the Blend Radius / Blend / Smooth parameter.
  3. Drag it up; the seam smooths in real time.
  4. Pick a profile if you want something other than Round.
  5. For Boolean, optionally tweak Material Blend to control color seam width.

Adjust modal (Ctrl + B)

Press Ctrl + B over an object that is a boolean or carve target to drag its blend radius live. You can also click the blend gizmo dot in the viewport to enter the same modal, see Interface: Gizmos.

ActionEffect
LMB-dragAdjust radius
Shift (while dragging)Precision mode: slow, fine adjustment
Ctrl (while dragging)Snap to round increments
1Round profile
2Sharp profile
3Soft profile
4Tight profile
5Chamfer profile
SToggle radius ↔ Chamfer Smooth (only useful when profile = Chamfer)
Enter / Space / LMB-releaseConfirm
Esc / RMBCancel

The viewport updates in real time, so you see the seam smooth out across booleans, carves, mirrors, arrays, and emboss/engrave as you drag.

See also