enter image description hereHi all, I am a student and a newbie in using blender. I just know the basic for the modelling and animate with time frame. I want to make an animation for brushing teeth but I don't know how to animate the bristle. I want to make the bristle to be soft and bending when contacting the surface of the Teeth and not penetrating into the teeth model. below i have attach the sample animation picture that i made but the bristle is not real as it penetrate into the teeth model. Can anyone help to teach me how to make the bristle soft and deform/bend when contacting the surface of the teeth? I really appreciate your help. Thank you everyone!

  • $\begingroup$ have you tried particle system? you can change stiffness and other values for realistic results . but i think some bones will do better and you dont need simulation for it( i mean bendy bones) $\endgroup$
    – MohMehdi
    Commented Jan 31, 2021 at 17:07

1 Answer 1


As suggested by mma78 in the comment try a Hair Particle System.

brushing the default cube
Brushing the default cube

  1. Make an emitter plane:

    • Copy a few faces of the lower side of the toothbrush head where the brushes sit. In Edit mode, duplicate Shift+D, press Esc or RMB to leave it where it is, and separate selection with P)
    • In Object mode, rename the plane, and parent it to the toothbrush (Ctrl+P). Parent must be selected last = highlighted light orange.
  2. Add a Hair Particle System to the bristle plane

    • 150 particles
    • 3, 5, or 8 segments (I used 8. Test it, less can make the bristle stiffer)
  3. In Field Weights turn off gravity:

    • Gravity: 0.000 (we do not want to bend the bristles to the ground)
  4. Adjust these values for render and the shape/appearance of the bristles:

    • Render:

      • [_] Show Emitter (disabled, we don't want to render it)
      • PathSteps: 5
    • Viewport Display:

      • Strand Steps: 5
    • Children: Simple

      • Radius: 0.02m (adjust this to your toothbrush size! Value here is for the 2m default cube!)
      • Roundness: 1.000
    • Clumping:

      • [X] Use Clump Curve
      • (edit a curve. Make it round in the top right corner. This makes the bristles heads round)
    • Hair Shape:

      • Strand Shape: -0.850 (for rounded bristles)
      • Diamenter Root: 0.3m (adjust this to your toothbrush size!)
  5. enable [X] Hair Dynamics. Run/bake the simulation and play with the Hair Dynamics values:

    • Collision
      • Distance: 5cm (adjust this to your toothbrush size!)
    • Pin Goal Strength: 10
    • Structure:
      • Vertex Mass: 0.3 kg (default, higher values make the bristles inert)
      • Stiffness: 30 (higher values result in less bending)
      • Damping: 0.300 (default, increase if the bristles swing too much)

Happy teeth brushing!

  • $\begingroup$ thanks for the reference, but what about the settings for collision sir? $\endgroup$
    – youthcloud
    Commented Jun 19, 2023 at 17:11

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