PyNanoInstantMeshes

Python bindings for Instant Meshes, a tool for automatic remeshing of 3D surfaces.

Installation

pip install PyNanoInstantMeshes

Usage

import numpy as np
import pynanoinstantmeshes as PyNIM

# vertices: float32 numpy array of shape (N, 3)
# faces:    uint32  numpy array of shape (M, 3)
new_verts, new_faces = PyNIM.remesh(vertices, faces, vertex_count=1000)

Example with trimesh

import trimesh
import numpy as np
import pynanoinstantmeshes as PyNIM

# Load or create a mesh
mesh = trimesh.primitives.Capsule(radius=1, height=2).to_mesh()

vertices = np.asarray(mesh.vertices, dtype=np.float32)
faces    = np.asarray(mesh.faces,    dtype=np.uint32)

# Remesh to approximately 500 vertices
new_verts, new_faces = PyNIM.remesh(vertices, faces, vertex_count=500)

result = trimesh.Trimesh(vertices=new_verts, faces=new_faces)
result.show()

API Reference

pynanoinstantmeshes.remesh

pynanoinstantmeshes.remesh(
    verts,
    faces,
    vertex_count,
    rosy=4,
    posy=4,
    scale=-1.0,
    face_count=-1,
    creaseAngle=0.0,
    align_to_boundaries=False,
    extrinsic=True,
    smooth_iter=0,
    knn_points=1000,
    deterministic=False,
) -> tuple[np.ndarray, np.ndarray]

Remeshes the input mesh and returns the new mesh as a (vertices, faces) tuple.

Parameters

Parameter	Type	Default	Description
verts	np.ndarray (N×3, float32)	—	Input vertex positions.
faces	np.ndarray (M×3, uint32)	—	Input triangle faces. Pass an empty array to treat verts as a point cloud.
vertex_count	int	—	Target number of vertices in the output mesh. Mutually exclusive with scale and face_count; the first positive value among the three is used.
rosy	int	4	Rotational symmetry order of the orientation field (2 or 4).
posy	int	4	Positional symmetry order (4 = quad output, 6 = triangle output).
scale	float	-1.0	Target edge length. When positive, overrides vertex_count and face_count.
face_count	int	-1	Target number of faces in the output mesh. Used when positive and scale ≤ 0.
creaseAngle	float	0.0	Dihedral-angle threshold (degrees) for crease detection. Edges whose dihedral angle exceeds this value are treated as sharp creases.
align_to_boundaries	bool	False	When True, aligns the orientation field to mesh boundaries.
extrinsic	bool	True	Use extrinsic (world-space) rather than intrinsic (surface-space) smoothness for the orientation field.
smooth_iter	int	0	Number of Laplacian smoothing iterations applied to the output mesh.
knn_points	int	1000	Number of nearest neighbours used when processing a point cloud (faces is empty).
deterministic	bool	False	Use a deterministic (single-threaded) algorithm for reproducible results.

Returns

A tuple (new_verts, new_faces) where:

• new_verts – np.ndarray of shape (V, 3), float32 — output vertex positions.
• new_faces – np.ndarray of shape (F, D), uint32 — output face indices, where D = 4 for quad meshes (posy=4) and D = 3 for triangle meshes (posy=6).

See Also

• tests/test_remeshing.py — comprehensive test cases covering all parameters.
• Instant Meshes paper — the underlying algorithm.