meshing.simplify_mesh

meshing.simplify_mesh(
    mesh,
    sdf,
    *,
    error,
    preserve_features=True,
    feature_mask=None,
    feature_angle=30.0,
    max_passes=100,
)

Simplify a dual-contour mesh by error-bounded, feature-safe collapses.

Repeatedly applies batches of independent half-edge collapses (see the module docstring for the guarantees) until no collapse passes the error bound and the safety checks. Because collapses are half-edge, every surviving vertex keeps its extracted position bitwise; with preserve_features (the default) all vertices on sharp mesh edges — box corners, crease chains, CSG seams — survive unchanged.

Parameters

Name	Type	Description	Default
mesh	Mesh	The extracted mesh to simplify.	required
sdf	Callable[[Array], Array]	The implicit field the mesh was extracted from, mapping one point `(3,)` to a scalar; used to reject collapses whose modified triangles stray from the zero set.	required
error	float	Positive deviation bound in world units. Bounds both the merged region’s RMS QEF error and the sampled field deviation (centroids and edge midpoints) of every modified triangle.	required
preserve_features	bool	Pin the endpoints of sharp mesh edges (dihedral angle above `feature_angle`) and any `feature_mask` rows. `False` disables both signals; boundary and non-manifold protection always stays on.	`True`
feature_mask	np.ndarray \| None	Optional boolean mask over the mesh’s vertex rows pinning extra vertices — for example non-`FACE` rows from :func:`~cadjoint.meshing.features.classify_feature_cells` or seam rows from :func:`~cadjoint.meshing.features.detect_branch_changes`, both aligned with the vertex rows of the same extraction.	`None`
feature_angle	float	Dihedral angle in degrees, strictly between 0 and 180, above which a mesh edge counts as sharp.	`30.0`
max_passes	int	Safety cap on collapse passes; the loop normally stops earlier, when a pass applies no collapse.	`100`

Returns

Name	Type	Description
	Mesh	A new :class:`~cadjoint.meshing.dual_contouring.Mesh` whose vertices
	Mesh	are a subset of the input’s (positions, normals, and cells carried
	Mesh	over unchanged) with reindexed faces. `quads` is empty: collapsed
	Mesh	connectivity no longer corresponds to extraction quads.

Raises

Name	Type	Description
	ValueError	If `error` is not positive, `feature_angle` is not strictly between 0 and 180, `max_passes` is not positive, or `feature_mask` has the wrong shape.