How to Create and Use Drivers in Blender

This guide provides a clear overview of driver functionality in Blender and demonstrates how to create them. You will learn what drivers are, how they automate relationships between different object properties, and the exact step-by-step process to set up and configure your own drivers for animation and rigging workflows.

What is Driver Functionality in Blender?

In Blender, a Driver is a tool that allows you to control the value of one property using another property, a mathematical expression, or a short Python script. Instead of manually keyframing values, drivers create dynamic, automated relationships between objects and settings.

Drivers are represented visually in Blender's interface by a distinct purple highlight over the driven input field.

Common use cases include:

  • Controlling facial shape keys using armature bones.
  • Linking mechanical parts (e.g., rotating one gear automatically turns another at a specific ratio).
  • Changing a material's color or emission intensity based on an object's distance or position.

How Drivers Work

A driver relies on three main components:

  1. Target Property: The property being controlled (e.g., Object B's Z Rotation).
  2. Input Variable: The data source driving the value (e.g., Object A's X Location).
  3. Expression: A mathematical formula that processes the input variable to calculate the final output value (e.g., var * 2 or sin(var)).

Step-by-Step: How to Create a Driver in Blender

Step 1: Add the Driver

  1. Navigate to the property you want to control (the target).
  2. Right-click on the value field (e.g., the Scale or Rotation field).
  3. Select Add Driver from the context menu. A driver configuration pop-over menu will appear, and the field will turn purple.

Step 2: Set Up the Input Variable

In the driver pop-over window (or inside the Driver Editor):

  1. Locate the Variables section. By default, an input variable named var is created.
  2. Set the Type to Transform Channel (ideal for object movement/rotation/scale).
  3. In the Prop field, select the controlling object (the source).
  4. Set the Type to the specific axis you want to read (e.g., X Location).
  5. Set the Space to World Space or Local Space depending on your project needs.

Step 3: Define the Expression

  1. Go to the Expression field at the top of the driver settings.
  2. Enter a mathematical formula using the variable name.
    • Simple link: var
    • Scaled link: var * 0.5
    • Inverted link: -var
  3. Press Enter to apply the expression.

Editing and Managing Drivers

To fine-tune complex setups:

  • Open the Drivers Editor by switching your editor window type to Drivers (or press Ctrl + Tab while hovering over the Graph Editor).
  • The Drivers Editor provides an N-Panel on the right side where you can manage multiple variables, tweak Python expressions, and adjust response curves using the F-Curve tab.
  • To remove a driver, right-click the purple property field and select Delete Driver.