# trimesh.proximity module¶

## proximity.py¶

Query mesh- point proximity.

Classes

 `ProximityQuery`(mesh) Proximity queries for the current mesh.

Functions

 `closest_point`(mesh, points) Given a mesh and a list of points find the closest point on any triangle. `closest_point_naive`(mesh, points) Given a mesh and a list of points find the closest point on any triangle. `longest_ray`(mesh, points, directions) Find the lengths of the longest rays which do not intersect the mesh cast from a list of points in the provided directions. `max_tangent_sphere`(mesh, points[, inwards, …]) Find the center and radius of the sphere which is tangent to the mesh at the given point and at least one more point with no non-tangential intersections with the mesh. `nearby_faces`(mesh, points) For each point find nearby faces relatively quickly. `signed_distance`(mesh, points) Find the signed distance from a mesh to a list of points. `thickness`(mesh, points[, exterior, normals, …]) Find the thickness of the mesh at the given points.
class `trimesh.proximity.``ProximityQuery`(mesh)

Bases: `object`

Proximity queries for the current mesh.

Methods

 `on_surface`(**kwargs) Given list of points, for each point find the closest point on any triangle of the mesh. `signed_distance`(points) Find the signed distance from a mesh to a list of points. `vertex`(points) Given a set of points, return the closest vertex index to each point
`on_surface`(**kwargs)

Given list of points, for each point find the closest point on any triangle of the mesh.

Parameters

points ((m,3) float, points in space) –

Returns

• closest ((m,3) float, closest point on triangles for each point)

• distance ((m,) float, distance)

• triangle_id ((m,) int, index of closest triangle for each point)

`signed_distance`(points)

Find the signed distance from a mesh to a list of points.

• Points OUTSIDE the mesh will have NEGATIVE distance

• Points within tol.merge of the surface will have POSITIVE distance

• Points INSIDE the mesh will have POSITIVE distance

Parameters

points ((n,3) float, list of points in space) –

Returns

signed_distance

Return type

(n,3) float, signed distance from point to mesh

`vertex`(points)

Given a set of points, return the closest vertex index to each point

Parameters

points ((n,3) float, list of points in space) –

Returns

• distance ((n,) float, distance from source point to vertex)

• vertex_id ((n,) int, index of mesh.vertices which is closest)

`trimesh.proximity.``closest_point`(mesh, points)

Given a mesh and a list of points find the closest point on any triangle.

Parameters
• mesh (trimesh.Trimesh) – Mesh to query

• points ((m, 3) float) – Points in space

Returns

• closest ((m, 3) float) – Closest point on triangles for each point

• distance ((m,) float) – Distance

• triangle_id ((m,) int) – Index of triangle containing closest point

`trimesh.proximity.``closest_point_naive`(mesh, points)

Given a mesh and a list of points find the closest point on any triangle.

Does this by constructing a very large intermediate array and comparing every point to every triangle.

Parameters
• mesh (Trimesh) – Takes mesh to have same interfaces as closest_point

• points ((m, 3) float) – Points in space

Returns

• closest ((m, 3) float) – Closest point on triangles for each point

• distance ((m,) float) – Distances between point and triangle

• triangle_id ((m,) int) – Index of triangle containing closest point

`trimesh.proximity.``longest_ray`(mesh, points, directions)

Find the lengths of the longest rays which do not intersect the mesh cast from a list of points in the provided directions.

Parameters
• points ((n,3) float, list of points in space) –

• directions ((n,3) float, directions of rays) –

Returns

signed_distance

Return type

(n,) float, length of rays

`trimesh.proximity.``max_tangent_sphere`(mesh, points, inwards=True, normals=None, threshold=1e-06, max_iter=100)

Find the center and radius of the sphere which is tangent to the mesh at the given point and at least one more point with no non-tangential intersections with the mesh.

Masatomo Inui, Nobuyuki Umezu & Ryohei Shimane (2016) Shrinking sphere: A parallel algorithm for computing the thickness of 3D objects, Computer-Aided Design and Applications, 13:2, 199-207, DOI: 10.1080/16864360.2015.1084186

Parameters
• points ((n,3) float, list of points in space) –

• inwards (bool, whether to have the sphere inside or outside the mesh) –

• normals ((n,3) float, normals of the mesh at the given points) – None, compute this automatically.

Returns

• centers ((n,3) float, centers of spheres)

`trimesh.proximity.``nearby_faces`(mesh, points)

For each point find nearby faces relatively quickly.

The closest point on the mesh to the queried point is guaranteed to be on one of the faces listed.

Does this by finding the nearest vertex on the mesh to each point, and then returns all the faces that intersect the axis aligned bounding box centered at the queried point and extending to the nearest vertex.

Parameters
• mesh (Trimesh object) –

• points ((n,3) float , points in space) –

Returns

candidates

Return type

(points,) int, sequence of indexes for mesh.faces

`trimesh.proximity.``signed_distance`(mesh, points)

Find the signed distance from a mesh to a list of points.

• Points OUTSIDE the mesh will have NEGATIVE distance

• Points within tol.merge of the surface will have POSITIVE distance

• Points INSIDE the mesh will have POSITIVE distance

Parameters
• mesh (Trimesh object) –

• points ((n,3) float, list of points in space) –

Returns

signed_distance

Return type

(n,3) float, signed distance from point to mesh

`trimesh.proximity.``thickness`(mesh, points, exterior=False, normals=None, method='max_sphere')

Find the thickness of the mesh at the given points.

Parameters
• points ((n,3) float, list of points in space) –

• exterior (bool, whether to compute the exterior thickness) – (a.k.a. reach)

• normals ((n,3) float, normals of the mesh at the given points) – None, compute this automatically.

• method (string, one of 'max_sphere' or 'ray') –

Returns

thickness

Return type

(n,) float, thickness