How to Enable Dynamic Hair Collisions in Blender

This guide explains Blender’s dynamic hair collisions feature and provides step-by-step instructions on how to enable and configure it in your 3D scenes. You will learn the mechanics behind hair simulation physics, how to designate collision meshes, and how to fine-tune settings to prevent hair strands from clipping through character meshes or surrounding objects during animation.

What Are Dynamic Hair Collisions?

Dynamic hair collisions refer to a physics-based simulation system in Blender where individual hair strands react realistically to movement and physical obstacles. Instead of remaining static or penetrating the character's geometry during motion, hair with dynamic collisions detects the surface boundaries of surrounding objects and deforms or slides across them naturally.

How to Enable Dynamic Hair Collisions

Setting up hair collisions in Blender requires configuring two main components: the collision object and the hair particle system.

Step 1: Configure the Collision Object

Before hair can interact with a surface (such as a character's body or clothing), that surface must be designated as a collider:

  1. Select the mesh object that the hair should collide with (e.g., character body, shoulders, or clothing).
  2. Open the Physics Properties tab in the Properties editor on the right.
  3. Click on the Collision modifier to add it to the selected object.
  4. Under the Softbody & Cloth panel inside the Collision settings, adjust the Outer and Inner thickness parameters to define the invisible collision boundary around the mesh.

Step 2: Enable Hair Dynamics on the Particle System

Once the collider is ready, you must activate the physics solver on the hair system:

  1. Select the mesh that emits the hair particles.
  2. Go to the Particle Properties tab and select your hair particle system.
  3. Check the box labeled Hair Dynamics.
  4. Expand the Hair Dynamics section to access simulation parameters:
    • Quality Steps: Increase this value (typically between 4 and 8) to reduce clipping and improve collision accuracy at the cost of simulation speed.
    • Pinning: Adjust the stiffness and mass to control how rigid or flexible the hair roots and strands are.

Step 3: Configure Modifier Order

The order of modifiers in the Modifier Properties tab significantly impacts collision detection:

  • Ensure the Collision modifier is placed below any armature or deforming modifiers on your character mesh so collisions are evaluated on the posed geometry.
  • On the hair emitter object, the Particle System modifier should generally be placed below armature deformers for proper movement evaluation.

Step 4: Bake and Preview the Simulation

  1. Go to the Particle Properties tab under the hair system.
  2. Expand the Cache section.
  3. Set your desired frame start and end range.
  4. Click Bake to calculate the hair movement and collision physics.
  5. Play back the timeline to view the dynamic collisions in the 3D viewport.