> 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/3d-multi-sensor-fusion/labeling/category-schema.md).

# Category Schema

## Ontologies

A Category Schema is defined as the project ontology with its classes and their attributes and associations.

<div data-with-frame="true"><figure><img src="/files/TCzEEeXLjZxZ4UIpCOs8" alt=""><figcaption></figcaption></figure></div>

Once the ontology is created under the Category Schema, it will appear in the following way on the tool:

<div data-with-frame="true"><figure><img src="/files/qXjUvvXBZlSegfmzGx1y" alt=""><figcaption></figcaption></figure></div>

***

To create the ontology click on Add Category

<div data-with-frame="true"><figure><img src="/files/r0n6qHG1Nvn3rXLJIXen" alt=""><figcaption></figcaption></figure></div>

### PCT (Class Level)

To add a new class/category\
For more info - [goto](#pct-class-level)

### Classifications (Task or Sequence Level)

Boolean

Single-Select Dropdown

Multi-select Dropdown

Text

For more info - [goto](/3d-multi-sensor-fusion/labeling/category-schema/classifications.md)

### Relations (Relationships of Objects)

Many

For more info - [goto](/3d-multi-sensor-fusion/labeling/category-schema/relations.md)