---
title: Blending
order: 3
---

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](../assets/gizmo-blending.webp)

## Where blending lives

| Modifier | Setting | Range |
|---|---|---|
| Boolean | *Blend Radius* | `0.0–10.0`, soft max `2.0` |
| Carve | *Outer* (with the *Blend* toggle) | soft max `2.0` |
| Bisect | *Blend*, plus *Corner Blend* per polyline plane | soft max `2.0` |
| Mirror | *Mirror Blend* | `0.0–2.0`, soft max `0.5` |
| Array (Line / Circle) | *Smooth* | `0.0–2.0`, soft max `0.5` |
| Emboss / Engrave | *Blend Radius* (outer) and *Inner Radius* (inner) | `0.0–10.0` |
| Smooth | *Radius*: a floor for every join above | soft 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](profiles.md))
- **Blend Smooth** *(Chamfer only)*: softens the chamfer's edges
- **Material Blend**: width multiplier for the *color* seam, independent of the geometry blend (see [Profiles](profiles.md#material-blend))

## 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](../modifiers/carve.md) 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](../modifiers/bisect.md) 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](../modifiers/smooth.md) 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](../interface/gizmos.md).

| Action | Effect |
|---|---|
| **LMB-drag** | Adjust radius |
| **Shift** *(while dragging)* | Precision mode: slow, fine adjustment |
| **Ctrl** *(while dragging)* | Snap to round increments |
| **`1`** | Round profile |
| **`2`** | Sharp profile |
| **`3`** | Soft profile |
| **`4`** | Tight profile |
| **`5`** | Chamfer profile |
| **`S`** | Toggle radius ↔ Chamfer Smooth (only useful when profile = Chamfer) |
| **Enter / Space / LMB-release** | Confirm |
| **Esc / RMB** | Cancel |

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

- [Rounding](rounding.md): primitive edge rounding (`B` modal)
- [Profiles](profiles.md): the five profile shapes
- [Modifiers: Boolean](../modifiers/boolean.md): full boolean parameter list
- [Modifiers: Smooth](../modifiers/smooth.md): one radius for the whole model
- [Interface: Gizmos](../interface/gizmos.md): viewport gizmos that open this modal