> ## Documentation Index
> Fetch the complete documentation index at: https://docs.speckle.systems/llms.txt
> Use this file to discover all available pages before exploring further.
# More Extensions
# More Extensions
We'll be expanding on our [basic example](/developers/viewer/examples/basic-example) by adding some of the stock viewer extensions.
## Section Tool
The stock section extension provides 6 customisable section planes by default placed as a axis aligned box. Additional to the tool itself there is also the section outlines display provided as another optional extension.
```typescript theme={null}
const sections = viewer.createExtension(SectionTool);
viewer.createExtension(SectionOutlines);
```
The section tools comes with a control gizmo by default, but we can also control it programatically. So if we want to set the section box to a particular size we can do:
```typescript theme={null}
/** Enable the section tool */
sections.toggle();
/** Programatically apply a section box */
const box = new Box3().copy(viewer.getRenderer().sceneBox);
box.max.z *= 0.6;
sections.setBox(box);
```
## Measurements Tool
The default measurement tool provides basic functionality for most measuring needs. There are two main measuring modes:
* **PointToPoint**: Classic measurement mode where you measure the distance between two defined points
* **Perpendicular**: This measuremente mode allows you to measure the distance along one point on a surface along it's normal to another chosen point.
* **AutoLazer™**: Double clicking when in perpendicular mode, automatically measures from the current point to the nearest surface along the current point's surface normal
## Differ
The differ provides diffing functionality between models. It can provide a diff data-wise as well as visually. Diffing works by taking a *current* model and comparing it against an *incoming* model. The result will contain added/removed/modified/unchanged objects which are colored accordingly (if visual diff is enabled). Diff results are based on object `id`s and `applicationId`s.