How to Break Rigid Bodies on Impact in Blender

Breaking a rigid body object on impact in Blender involves fracturing a mesh into individual pieces, applying active rigid body physics to each fragment, and binding them together using breakable rigid body constraints. When a projectile or collision force exceeds the defined threshold of these constraints, the bonds break instantly, creating a realistic shattering effect. This guide details the step-by-step process to set up mesh fracturing, rigid body dynamics, and breakable constraint networks.

Step 1: Fracture the Object

  1. Enable the built-in Cell Fracture add-on by navigating to Edit > Preferences > Add-ons and searching for "Cell Fracture."
  2. Select your target object in the 3D Viewport.
  3. Press F3, type Cell Fracture, and select the tool.
  4. Set the Point Source (such as Own Vertices or an Annotation pencil sketch) and adjust the Source Limit to control the number of pieces.
  5. Click OK to generate the fractured pieces. Move the original unbroken object to a hidden collection.

Step 2: Set Up Rigid Body Physics

  1. Select all the generated fractured pieces.
  2. In the 3D Viewport header, go to Object > Rigid Body > Add Active.
  3. In the Physics Properties panel, ensure the Type is set to Active and the Collision Shape is set to Convex Hull.
  4. Set the mass of the individual pieces appropriately based on the material scale.

Step 3: Connect Fragments with Rigid Body Constraints

  1. Keep all fractured pieces selected.
  2. In the viewport menu, navigate to Object > Rigid Body > Connect.
  3. In the operator pop-up menu at the bottom-left of the viewport:
    • Set Type to Fixed.
    • Set Pattern to Adjacent.
  4. With all constraint empties selected, open the Physics Properties panel for one constraint.
  5. Check the Breakable box.
  6. Set the Threshold value. This determines the amount of impact force required to sever the connection between adjacent pieces (a lower value breaks easily; a higher value resists impact).
  7. Right-click the Breakable checkbox and select Copy to Selected, then right-click the Threshold value and select Copy to Selected to apply these settings across all generated constraints.

Step 4: Add the Collider Object

  1. Add the projectile or ground object that will trigger the impact.
  2. Go to the Physics Properties panel and click Rigid Body.
  3. If using an animated projectile, set the Type to Active, check Animated, and keyframe its movement directly into the fractured object.
  4. If using a stationary obstacle or floor, set the Type to Passive.

Step 5: Test and Refine the Simulation

  1. Press Spacebar to play the physics simulation and observe the impact.
  2. If the object shatters prematurely before impact, increase the Threshold value on the constraints or decrease the mass of the fractured pieces.
  3. If pieces clip through each other or behave erratically, go to Scene Properties > Rigid Body World and increase the Substeps Per Frame and Solver Iterations to improve accuracy.
  4. Once the simulation behaves as desired, go to the Cache sub-panel in the Rigid Body World settings and click Bake.