---
title: Performance
order: 2
---

The Performance panel affects the viewport only. It sets how the cell size follows each object's size, and how much quality the viewport gives up while you orbit or drag. [F12](f12-render.md) always renders at full quality.

![the Performance panel](../assets/rendersettings-performance.webp)

## Settings

| Setting | Default | Range | What it does |
|---|---|---|---|
| **Auto Cell Size** | on | | Scale [World Cell Size](quality.md#settings) for each object by the object's size, so a large object gets about the same detail and cost as a small one. Off = one cell size for the whole scene. |
| **Progressive Refinement** | on | | While you orbit, pan or drag, draw a coarser picture that is faster to draw; once you stop, refine it to full quality in steps. Off = full quality on every frame. |
| **Target FPS** | `144` | `5 – 200` | The frame rate the moving picture tries to keep. When frames take too long the picture gets coarser, and when there is time to spare it gets finer again. |
| **Refinement Steps** | `4` | `1 – 12` | The number of steps from the coarsest picture to full quality. `1` = always full quality. |
| **Min Resolution** | `30%` | `1 – 100%` | The resolution of the coarsest picture. |
| **Min Steps** | `64` | `4 – 128` | The *Max Steps* of the coarsest picture. |
| **Min Threshold** | `0.0020` | `0.0001 – 0.05` | The *Hit Threshold* of the coarsest picture. Set it equal to *Hit Threshold* if silhouettes shift while the picture refines. |

The settings under *Progressive Refinement* are greyed out while it is off. While the picture refines, the text in the top-left corner of the viewport shows the current step, for example *Chisel: 2/4*.

## Auto Cell Size

*World Cell Size* is a length, so without *Auto Cell Size* an object eight times larger needs about 64 times as many cells at the same setting. With it on, *World Cell Size* is the cell for an object one Blender unit across, and each object's cell grows or shrinks with its size. The size is taken from the surface area of the object's bounding box, so a long, thin part such as a rail keeps the detail its thickness needs.

## Still view: full resolution

![the view stops, the reduced picture shows, then the full-resolution picture replaces it (zoomed in)](../assets/still-sharpen.webp)

When every 3D view has been still for 0.3 s, Chisel draws the view again at full resolution and swaps the sharp picture in once it is complete. This happens whenever *Resolution* is below `100%`; there is no separate setting. Any orbit, edit or setting change goes back to the normal picture straight away. On a light model the sharp picture arrives in under half a second; on very heavy scenes it can take several seconds.

## Rendered shading of plain scenes

If a scene contains only Spheres, Boxes, Cylinders, Capsules, Tori and unrounded Cones, joined by Boolean modifiers and Solidify, *Rendered* shading and F12 draw it about a third faster, and hard edges no longer show a thin light line along the crease. A scene with any other shape or modifier is drawn the usual way.

## Camera navigation

When you orbit, pan or zoom without editing anything, the view shows a simplified mesh of the shapes, with flat colour and simple lighting, so the camera moves smoothly. The full picture comes back when the camera stops.

## Editing

- When you drag part of a model, only the changed part of the shape, and of the view, is updated.
- During a drag, the fine detail around booleans is updated when you release the mouse.
- Moving a whole object does not recompute its shape. Undo, redo, or typing back a value you had before reuses the earlier result.

> [!tip] Smooth orbits on heavy scenes
> Lower *Min Resolution* if orbiting is not smooth. The picture still refines to full quality when you stop.

## Limits

> [!warning] 256 shapes per object
> An object and all the shapes its modifiers use can hold up to **256 shapes**. The Chisel Modifiers panel shows the count as *Objects N/256* and turns it red at 80%. Shapes past the limit are not drawn.

- Releasing a drag on a very heavy scene can pause for a moment.
- The first time a new kind of shape or modifier is used in a session (an Ngon, Text or path shape, a Prism-type shape, a Twist, Bend, Bisect or Carve), the view can pause briefly while its [shaders compile](../getting-started/installation.md#shader-compilation).