Function boolean 

pub fn boolean(
    topo: &mut Topology,
    op: BooleanOp,
    a: SolidId,
    b: SolidId,
) -> Result<SolidId, OperationsError>

Perform a boolean operation on two solids.

Uses the GFA pipeline as the primary engine, with mesh boolean (co-refinement) as a fallback when GFA fails or produces invalid results.

Errors

Returns an error if either solid is invalid or the operation produces an empty or non-manifold result.