How to Create Custom Light Falloff in Blender

This guide explains how to set up and customize light falloff nodes for light objects in Blender using the Cycles render engine. By replacing the default inverse-square attenuation with custom node networks, you can create stylized lighting, control light reach precisely, and prevent scene burnout without sacrificing ambient illumination.

1. Switch to Cycles and Enable Nodes

Blender’s custom light falloff nodes function natively in the Cycles render engine.

  1. Set the render engine to Cycles in the Render Properties panel.
  2. Select the light source (Point, Spot, Area, or Sun) in your 3D Viewport or Outliner.
  3. Open the Object Data Properties (light bulb icon) in the Properties panel and click Use Nodes, or split your workspace and open the Shader Editor with the light selected.

2. Add the Light Falloff Node

  1. In the Shader Editor, ensure you are viewing the Object shader type. You will see an Emission node connected to the Light Output node by default.
  2. Press Shift + A and go to Color > Light Falloff (or search for "Light Falloff").
  3. Place the node to the left of the Emission node.

3. Understand the Output Sockets

The Light Falloff node provides three different attenuation models:

  • Quadratic: Standard physically accurate inverse-square falloff (\(1 / distance^2\)).
  • Linear: Slower, linear light decay (\(1 / distance\)).
  • Constant: Light maintains full intensity regardless of distance (\(1 / 1\)).
  • Smooth Input: Softens the light at points extremely close to the light source to prevent overexposed highlights.

4. Build a Custom Falloff Network

To customize the decay curve beyond the standard mathematical presets:

  1. Connect either the Linear or Quadratic output of the Light Falloff node into a modifier node.
  2. Press Shift + A and add a Converter > Math node or a Converter > Color Ramp node.
  3. Insert the math node between the Light Falloff node and the Strength input of the Emission node.

Custom Decay Profiles:

  • Hard Distance Cutoff: Set a Math node to Less Than or use a Color Ramp with a Constant interpolation to create a defined threshold where the light abruptly stops.
  • Non-Photorealistic/Stylized Decay: Use a Color Ramp node set to Linear or Ease. Adjust the gradient stops to precisely map which distances receive full brightness, partial illumination, or complete darkness.
  • Controlled Dimming: Use a Math node set to Multiply or Power to adjust the rate of decay without losing smooth edge transitions.

5. Finalize the Connection

  1. Connect the output of your custom node chain (such as the Color Ramp or Math result) into the Strength socket of the Emission node.
  2. Adjust the initial Strength slider on the Light Falloff node to control the overall power of the light while preserving your custom falloff curve.