# trimesh.proximity¶

## 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_corresponding`(triangles, points) Return the closest point on the surface of each triangle for a list of corresponding points. `closest_point_naive`(mesh, points) Given a mesh and a list of points find the closest point on any triangle. `group_min`(groups, data) Given a list of groups find the minimum element of data within each group `log_time`(method) A decorator for methods which will time the method and then emit a log.debug message with the method name and how long it took to execute. `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. `points_to_barycentric`(triangles, points[, …]) Find the barycentric coordinates of points relative to triangles. `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 to surface

• 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) – Points in space

Returns

signed_distance – Signed distance from point to mesh.

Return type

(n, 3) float

`vertex`(points)

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

Parameters

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

Returns

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

• vertex_id ((n,) int) – Index of mesh.vertices for closest vertex.

`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 to mesh.

• 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) – Points in space.

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

Returns

signed_distance – Length of rays.

Return type

(n,) float

`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) – Points in space.

• inwards (bool) – Whether to have the sphere inside or outside the mesh.

• normals ((n, 3) float or None) – Normals of the mesh at the given points if is None computed 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.Trimesh) – Mesh to query.

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

Returns

candidates – Sequence of indexes for mesh.faces

Return type

(points,) int

`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.Trimesh) – Mesh to query.

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

Returns

signed_distance – Signed distance from point to mesh

Return type

(n, 3) float

`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) – 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 If is None computed automatically.

• method (string) – One of ‘max_sphere’ or ‘ray’

Returns

thickness – Thickness at given points.

Return type

(n,) float