---
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` |
| 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` |

## 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.

## 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 with a boolean 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 / LMB-release** | Confirm |
| **Esc / RMB** | Cancel |

The viewport updates in real time, so you see the seam smooth out across booleans, 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
- [Interface: Gizmos](../interface/gizmos.md) — viewport gizmos that open this modal