# Custom Dimension
## Overview
A **Custom Dimension** in ReOrc allows users to define new categorical fields within a Cube that do not exist directly in the underlying data model. Custom Dimensions enhance analytical capabilities by enabling additional grouping, filtering, and segmentation of data.
## What is Custom Dimension?
A **Custom Dimension** is a user-defined field that categorizes data based on computed logic, transformations, or predefined criteria. These dimensions help refine analyses without modifying the raw dataset.
## Use Cases
Custom Dimensions are used when:
* **Derived Categorization**: Creating new classifications, such as grouping age into "Youth," "Adult," and "Senior."
* **Conditional Labels**: Assigning custom labels based on business rules, such as "High Value Customer" for those with purchases over a threshold.
* **Combining Attributes**: Merging multiple fields into a single dimension, like concatenating `Region` and `Sales Territory`.
* **Data Standardization**: Normalizing values across different datasets to ensure consistency.
## Create a Custom Dimension
To create a custom dimension, follow these steps:
{% hint style="info" %}
Ensure the cube's primary key has been set before proceed to create the custom dimension. Refer [Cube](/semantic-modeling/cube.md#create-cube)
{% endhint %}
1. Click on **+** button, select **Add a dimension**
2. Fill in the details in the modal:
1. **Field label** will be auto populate based on the Field name
2. When entering the **custom formula**, you can click on the fields on the list to auto populate into the formula box.
3. Click on **Validate** button to validate the formula
{% hint style="warning" %}
Ensure that the custom formula matches the type of database connected.
{% endhint %}
4. Once no error detected, click on **Add** button to add the custom dimension into the cube.
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