---
title: Core Concepts
order: 3
---

Short definitions of the terms this manual uses, each linked to the page that covers it.

## Shapes and stacks

### Shape

A Blender object that Chisel draws from a distance field instead of from its mesh. Its **Type** (Box, Tube, Text and so on) and its own settings are in *Object Properties ▸ SDF*. See [Primitives](../primitives/index.md).

### Modifier

One step that changes a shape: a join, a cut, a mirror, an array, a bend and so on. Chisel's modifiers live in the **Chisel Modifiers** panel, not in Blender's modifier stack. See [Modifiers](../modifiers/index.md).

### Stack (the tape)

A shape's modifiers in the order they apply, from the top down. The [Tape tree](../interface/tape-tree.md) shows every stack of the scene. Order matters: a cut placed before a join leaves the joined shape whole, a cut placed after it cuts it too.

![The Tape tree lists Bowl (Difference) before Rod (Union): the rod runs across the bowl cut into the box](../assets/concepts-order-a.webp)

![The Tape tree lists Rod before Bowl: the bowl cuts through the rod as well](../assets/concepts-order-b.webp)

### Host

The shape whose stack holds a modifier. In the Tape tree, the host is the row the modifier sits under.

### Target

The shape a modifier's **Target** field names. A Boolean's target is the [cutter](#cutter), an Emboss or Engrave target the **stamp**, a Carve's target the **carve target**. The host is never called the target.

### Cutter

A Boolean's target. A new cutter stops rendering on its own (**Render** off) and shows a coloured [outline](../interface/gizmos.md#cutter-outlines) instead: red for Difference and Slice, green for Union, blue for Intersect. Click the shape where its outline is to select it.

### Join

A modifier that combines the host with a target. There are seven kinds: Union, Difference, Intersect, Slice, Emboss, Engrave and Carve. See [Joins](../joins/index.md).

### Point

A spot that defines part of a shape or a modifier: an Ngon's corner, a path shape's point, a Sweep's path, a Bisect fence's corner, a Lattice cage's control. You edit points in [Edit mode](../interface/edit-mode.md).

## Rounding and blending

### Rounding

The radius that rounds a shape's own edges, set on the shape. See [Rounding](../rounding-and-blending/rounding.md).

### Blend

The radius of the fillet where a join meets the host. Each join has its own. See [Blending](../rounding-and-blending/blending.md).

### Profile

The cross-section of a rounding or a blend: **Round**, **Sharp**, **Soft**, **Tight** or **Chamfer**. See [Profiles](../rounding-and-blending/profiles.md).

## Drawing

### Render (on or off)

A switch at the top of every shape's SDF panel. On (the default), Chisel draws the shape. Off, the shape is not drawn on its own but still works as a target, for example as a cutter. A shape with **Render** off that no stack uses is listed under **Unused** in the Tape tree. See [Display](../render-engine/display.md#render-switch-and-cutters).

### Ray-marched view and proxy mesh

In *Material Preview* and *Rendered* shading, the Chisel engine draws the shapes from their distance fields by ray marching. Blender also needs a mesh, for *Solid* shading, *EEVEE*, *Cycles*, snapping and selection. For a shape with modifiers, Chisel keeps a low-resolution **proxy mesh** of the result and updates it after each edit. See [Proxy mesh](../render-engine/display.md#proxy-mesh).

![The same model ray-marched, left, and as its proxy mesh in Solid shading with wireframe, right](../assets/concepts-proxy.webp)

## The Chisel tool

### Chisel tool

Chisel's workspace tool in the 3D View: the orange icon at the bottom of the tool bar, or `Alt + Q` from any tool. Most Chisel keys work only while it is active. See [Chisel Tool](../interface/active-tool.md).

### Mode

What a left drag does in Object mode: **Select**, **Create** (draw a new shape), **Block** (draw a base, then pull its height) or **Bisect** (draw a cutting line). See [Modes](../interface/active-tool.md#modes).

### Object mode and Edit mode

The Chisel tool's two states. In **Object** mode it works on whole shapes: selecting, adding, drawing, cutting, and the modifier handles. In **Edit** mode it works on the points of the selected shapes. `Tab` or the **Edit** button switches between them. Both are states of the tool: Blender itself stays in its Object Mode. See [Edit Mode](../interface/edit-mode.md).

### Handle

A dot, ring, arrow or arc drawn in the view on a selected shape or modifier. Drag it to change a value: a size, a rounding, a blend, a modifier's offset or angle. Also called a gizmo. See [Gizmos](../interface/gizmos.md).

## Where settings live

| What | Where |
|---|---|
| A shape's type and its own settings | *Object Properties ▸ SDF*, see [Properties Panels](../interface/panels.md) |
| A shape's stack | *Modifier Properties ▸ Chisel Modifiers*, see [Modifiers](../modifiers/index.md#the-modifier-stack) |
| A shape's colour | *Material Properties*, see [Materials](../materials/index.md) |
| The engine: quality, performance, matcap, display, gizmo switches, baking | *Render Properties*, with the render engine set to **Chisel**, see [Render Engine](../render-engine/index.md) |
| The tool's mode and its settings | The tool settings row above the view and the `D` popup, see [Chisel Tool](../interface/active-tool.md) |
| Which handles and overlays show | The gizmo icons and drop-down in the tool settings row, see [Gizmos](../interface/gizmos.md#tool-bar-switches) |
| Status, theme colours, GPU memory, debug tools | `Edit ▸ Preferences ▸ Add-ons ▸ Chisel`, see [Preferences](../preferences.md) |

## Units and detail

Every length in Chisel (sizes, rounding, blend, offsets) is a real distance in the scene, shown in the scene's units, so a model built in millimetres works the same as one built in metres. The viewport keeps detail down to **World Cell Size**, scaled to each object's size by **Auto Cell Size**, while an [F12 render](../render-engine/f12-render.md) always draws the exact surface; see [Quality](../render-engine/quality.md#settings).

## See also

- [Implicit Modeling](implicit-modeling.md): the math behind these terms
- [Interface](../interface/index.md): where each part of Chisel sits in the Blender window