Fracture
Break geometry into pieces, each carrying the physics metadata a simulation reads.
What it does
Fracture breaks a mesh into pieces for destruction. Geometry goes in and comes back as fragments carrying physics metadata: per-piece mass, volume, and centroid, plus adjacency data so a Physics Joint node can auto-constrain neighbouring pieces back together. Interior cut faces are tagged, so they can be shaded or shattered differently from the original surface.
There are two fracture strategies. Voronoi scatters (or accepts) sites and splits the mesh along the bisecting planes between them: brittle shatter, fast, and controlled by piece count and seed. Convex voxelises the mesh and runs a watershed decomposition into roughly convex chunks, the shape physics engines want for collision proxies rather than visual breakage.
When to use it
A destruction effect: glass, rock, concrete, or any brittle break
Physics-ready collision pieces for a rigid-body sim, through Convex mode
Cuts following a specific pattern: wire points (from Points, for example) into Fracture Source instead of the random site generator
A rough, uneven break rather than a clean cut: turn on Interior Noise
| Parameter | Type | Default | What it does |
|---|---|---|---|
geometry | Geometries or Primitives | — | What to break into pieces — a mesh, or 2D shapes and text outlines. Shapes break into flat polygon pieces clipped to their own outline, holes and counters included. |
source | Scalar Field or Color Field or SDF or Points or Vec3[] | "None" | What decides where the geometry breaks. Leave it unwired for a Voronoi shatter: the node scatters Piece Count points of its own and breaks the geometry into that many solid Voronoi chunks, controlled by Piece Count and Seed. Wire something here only for a break pattern that is NOT that — a pattern or noise field cuts the geometry into bands wherever the field's value steps, and a set of points cuts it into Voronoi chunks around your own points. Picking a preset drops that producer into the graph, already wired here, so its scale, seed and shape stay editable on that node. One of: None, Cracks, Rings, Noise, Points. |
piece_count | Number | 20 | How many pieces to aim for. With nothing wired it is the number of random break sites; with a pattern or noise field wired it is how finely that field is banded into pieces. |
seed | Number | 42 | — |
piece_offset | Number | 0 | Separation gap between pieces (0 = tight fit). Drag for 0–100; Shift-drag for fine, or type an exact value. |
Gotchas
Piece Offset creates a visible gap between pieces, useful for exploded previews, but it changes piece silhouettes. Return it to 0 before baking final collision shapes for physics.
Piece Data and Adjacency are only populated for Voronoi fractures, since Voronoi cells carry the per-piece IDs that data is grouped on. Convex mode's region-boundary output has no such IDs, so those outputs come back empty. That is expected, not a bug.
Fracture Source only shapes the break pattern in Voronoi mode. With nothing wired in, Voronoi generates random sites internally, controlled by Piece Count and Seed. Convex mode ignores Fracture Source entirely and decomposes from the voxel grid.
Voxel Resolution only applies in Convex mode. Raise it for cleaner collision pieces on large or detailed meshes, at a noticeable cost in speed.
Worked example
Wire a mesh into Geometry.
Leave Fracture Source unconnected and adjust Piece Count and Seed until the break pattern reads well.
Turn on Interior Noise and raise Noise Amplitude for a rougher break.
Nudge Piece Offset up to preview the shattered pieces separated in space.
For a physics simulation, switch Fracture Mode to Convex and tune Voxel Resolution, then feed Pieces into a rigid-body setup. Use Adjacency to auto-constrain neighbouring pieces with Physics Joints.
See also
Cube · Mesh · Convex Hull · Geometry (meshes)