Example: csg_operations
Figure 12.3 — Example: CSG Operations
Crate: cfd-suite (workspace root)
Run: cargo run --example csg_operations --features csg
Source: examples/csg_operations.rs
What This Example Demonstrates
Union, intersection, and difference on three primitive pairs (Cube × Cylinder,
Sphere × Cube, Cylinder × Sphere) using the Mesh Arrangement pipeline, with
full topology validation and STL export to outputs/csg/.
| Operation | API | Check |
|---|---|---|
| Union | csg_boolean(&a, &b, BooleanOp::Union) | Euler χ = 2, watertight |
| Intersection | csg_boolean(&a, &b, BooleanOp::Intersection) | Volume ≤ min(Va,Vb) |
| Difference | csg_boolean(&a, &b, BooleanOp::Difference) | Volume = Va − overlap |
Key Code Snippet
use cfd_mesh::application::csg::boolean::{csg_boolean, BooleanOp};
use cfd_mesh::{Cube, IndexedMesh};
use cfd_mesh::domain::geometry::primitives::{Cylinder, PrimitiveMesh};
let cube = Cube { origin: Point3r::new(-1.0,-1.0,-1.0),
width: 2.0, height: 2.0, depth: 2.0 }.build()?;
let cyl = Cylinder { radius: 0.6, height: 3.0, segments: 24 }.build()?;
let result = csg_boolean(&cube, &cyl, BooleanOp::Difference)?;
// result written to outputs/csg/cube_minus_cylinder.stlDiagnostic Tracing
CSG_TRACE=1 cargo run --example csg_operations --features csg
```text
Enables seam-repair trace output for investigating watertightness failures
after boolean operations.
## Book Chapter
[← Geometry Construction and CFD Coupling](../geometry_and_meshing.md)