Adjust Bump Node Distance and Strength in Blender

In Blender, the Bump node creates the illusion of surface detail without modifying geometry, primarily controlled through its Strength and Distance inputs. The Strength parameter adjusts the overall visibility and intensity of the effect, while the Distance parameter defines the physical height scale of the bumps in Blender units. Balancing these two settings allows you to transform flat surfaces into convincingly detailed materials like brick, leather, or brushed metal.

Understanding Strength vs. Distance

To adjust the Bump node effectively, it helps to understand how each parameter modifies your material:

  • Strength (0.0 to 1.0): Acts as a multiplier for the bump effect. A value of 0.0 disables the bump entirely, 0.5 gives a moderate effect, and 1.0 applies the full bump calculation. Values above 1.0 can be used, but they often produce harsh shading artifacts.
  • Distance: Measures the real-world depth or height of the surface variation. By default, Blender uses meters, meaning a Distance of 1.0 tells Blender the height difference between the highest and lowest points of the texture is 1 meter.

How to Adjust the Settings

  1. Open the Shader Editor and select the material applied to your object.
  2. Ensure your Bump node is connected:
    • Your height texture (e.g., Image Texture or Noise Texture) connects to the Height socket of the Bump node.
    • The Normal output of the Bump node connects to the Normal input of the Principled BSDF shader.
  3. Adjusting Strength:
    • Click and drag the Strength slider left or right, or click the field to type a specific value.
    • For subtle micro-details (such as skin pores or fine plastic grain), lower the Strength to between 0.100 and 0.300.
  4. Adjusting Distance:
    • Click the Distance numerical field and type a value appropriate for your object's scale.
    • Since default textures usually require small height variations, lower the Distance significantly. For fine surface textures, values between 0.001 (1 millimeter) and 0.010 (1 centimeter) yield realistic results.
  • Set Distance First: Base the Distance value on real-world measurements relative to your 3D model. If a brick mortar line is roughly 5 millimeters deep, set the Distance to 0.005.
  • Fine-Tune with Strength: Once the Distance reflects the real-world scale, adjust the Strength slider to blend the visibility of the effect into your lighting environment.
  • Avoid Excessively High Distance Values: Setting Distance too high causes dark, inverted shading borders along the mesh because Blender is trying to calculate exaggerated physical height on a flat polygon. If your bumps look black or broken, reduce the Distance value.