> For the complete documentation index, see [llms.txt](https://docs.imerit.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.imerit.net/labeling/labeling-tools/tools/angle.md).
# Angle
Overview of the Angle labeling tool in Ango Hub
The Angle labeling tool allows you to draw and measure angles in 3D medical assets.
{% hint style="info" %}
The Angle tool is supported across the DICOM and Medical labeling editors.
{% endhint %}
## How to add an Angle tool to your project
From the project’s *Settings* tab, enter the *Category Schema* section.
Click on *Add Category*. From the list that appears, click on *Angle*.
A new row will appear named *Angle*. Click on it to expand it.
**Schema ID**: A unique ID which identifies this class in your project.
**Title:** The name of your class.
**Required:** Whether or not annotators have to add at least one instance of this class in order to submit their annotation task.
If you would like to ask labelers further questions, for example, if you want to show a further *radio* after drawing the annotation, click on *Add Classification* and add a further question. [More on nested questions here](/labeling/labeling-tools/tools/nested-classifications.md).
### How to Draw an Angle
Click on the image where you’d like the angle vertex to be. Then, click on it or on its edge nodes to change its angle or where it is located.
## Example Export
This is what the Angle tool output looks like in the final export. See [its section on our documentation page on our export](/data/importing-and-exporting-annotations/exporting-annotations/ango-export-format/asset/task/tools.md#angle) for more.
```json
[
{
"asset": "https://angohub-test-assets.s3.eu-central-1.amazonaws.com/67ed4234d51cdf151a019b3e/assets/72579265-072d-4a8e-893f-1fd3225fd80c.nii.gz?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA3FV7TSYIZFWAQDUV%2F20250902%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20250902T112709Z&X-Amz-Expires=86400&X-Amz-Signature=3d6ee78dce799adc3f2eae6e1d77f0251bf27d63df24f7a54363f308d890d2df&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject",
"assetId": "67ed4269cce65e74f1a24a0d",
"externalId": "medical-compressed-nifti.nii.gz",
"batches": [],
"task": {
"taskId": "67ed4269cce65e74f1a24a1f",
"type": "default",
"stage": "Complete",
"stageId": "Complete",
"updatedAt": "2025-09-02T11:25:46.054Z",
"updatedBy": "example@example.net",
"totalDuration": 0,
"tools": [
{
"angle": {
"vertex": [
121,
112,
60
],
"p1": [
17,
166,
60
],
"p2": [
170,
176,
60
],
"angle": 100
},
"objectId": "5b1e9542a735f72f5edc815",
"classifications": [],
"schemaId": "e83ed8591f14d6c804f9919",
"title": "Angle Tool"
}
],
"classifications": [],
"relations": [],
"brushDataUrl": null,
"medicalBrushDataUrl": null
}
}
]
```
---
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