# Expression tool

> Open the expression editor and connect a property to dynamic, computed values.

Source: https://bluepic.io/help/expressions-and-logic/expression-tool  
Language: en  
Category: expressions-and-logic  
Last updated: 2026-06-16

Most properties in Bluepic hold a fixed value, like a colour or a number you type in. An **expression** lets a property compute its value instead, so it can react to input fields, other elements, or logic you define.

The expression tool, the **fx** button in the toolbar, is how you open the **expression editor**: click it, then click the property you want to make dynamic.

![](https://imagedelivery.net/mudX-CmAqIANL8bxoNCToA/817021ca-9de9-4ef8-b038-27bbee95ae00/max)

## The expression editor

The editor opens in a small movable window with two ways to work, switched with the icons in its top corner.

**Builder view** lets you assemble the expression from blocks. Browse the building blocks under four tabs and click to insert them:

![](https://imagedelivery.net/mudX-CmAqIANL8bxoNCToA/3b492cac-cea7-4d24-9a3d-c672bcd86100/max)

- **[Functions](https://bluepic.io/help/expressions-and-logic/functions)**: operations grouped by purpose, such as Math, Color, Logic, Animation, and Helpers.
- **[Elements](https://bluepic.io/help/expressions-and-logic/element-metadata-subproperties)**: data from other elements, like their position or size.
- **[Variables](https://bluepic.io/help/expressions-and-logic/variables)**: the values coming from your input fields.
- **[Static](https://bluepic.io/help/expressions-and-logic/static-values)**: fixed numbers, text, and colours.

Click **Update** to apply the expression to the property.

**Code view** lets you write the expression as text. **Prettify** reformats it to be easier to read.

![](https://imagedelivery.net/mudX-CmAqIANL8bxoNCToA/4410b45b-6e26-401a-34e4-f777681fcb00/max)

For the rules of writing expressions as text, see [Syntax](https://bluepic.io/help/expressions-and-logic/expression-syntax).

> If you already know the syntax, you can also skip the editor and type an expression straight into a property field, for example `text1.bottom + 20`.