Adjust Fluid Viscosity in Blender for Honey and Oil

Creating realistic thick fluids like honey or motor oil in Blender requires configuring the Mantaflow physics engine's viscosity parameters. This guide explains how to activate the fluid physics system, configure the viscosity Base and Exponent values, adjust surface tension, and apply the exact numerical settings needed to transform standard watery liquid into smooth oil or slow-pouring, sticky honey.

1. Set Up the Fluid Domain

  1. Select the bounding box intended as your simulation container and go to the Physics Properties tab.
  2. Click Fluid, set the Fluid Type to Domain, and change the Domain Type to Liquid.
  3. Create your emitter object inside the domain, set its Fluid Type to Flow, the Flow Type to Liquid, and the Flow Behavior to Inflow or Geometry.

2. Enable Viscosity Settings

  1. Select your Domain object and open the Physics Properties panel.
  2. Scroll down to the Viscosity section and check the box to enable it.
  3. Blender calculates viscosity using scientific notation via two fields:
    • Base: The primary numerical value.
    • Exponent: The power of ten multiplier (\(Base \times 10^{-Exponent}\)). A lower exponent results in a thicker fluid.

3. Configure Values for Oil

Motor oil and cooking oils are thicker than water but flow smoothly without extreme stickiness or coiling:

  • Viscosity Base: 1.0 to 5.0
  • Viscosity Exponent: 1 or 2
  • Surface Tension: Set to 0.0 or low values like 0.05 to prevent over-clumping.
  • Resulting Behavior: The liquid flows quickly around obstacles but exhibits a noticeable damping effect compared to water, resisting instant splashing.

4. Configure Values for Honey

Honey is a high-viscosity fluid that flows slowly, holds its shape temporarily, and creates a coiling effect when poured onto a surface:

  • Viscosity Base: 2.0 to 8.0
  • Viscosity Exponent: 0 (An exponent of 0 applies the full base value directly without fractional reduction)
  • Surface Tension: Enable Surface Tension in the Liquid settings and set the value between 1.0 and 2.5 to help the fluid hold together in strands and pools.
  • Resulting Behavior: The fluid streams downwards in thick ribbons, folds over itself, and settles gradually over time.

5. Optimize Simulation Quality

  • Resolution Divisions: Increase the domain resolution to at least 64 for testing and 128 to 256 for final bakes so that the thick fluid holds its volume and contours correctly.
  • Time Steps (Substeps): Under the Domain > Liquid settings, increase the Frame Substeps (Minimum: 2, Maximum: 4 or higher). High-viscosity simulations require more calculation sub-frames to prevent the fluid from exploding or jittering when stretching.