File IO

This tutorial shows how basic geometries are read and written by Open3D.

Point cloud

This code below reads and writes a point cloud.

print("Testing IO for point cloud ...")
pcd = o3d.io.read_point_cloud("../../TestData/fragment.pcd")
print(pcd)
o3d.io.write_point_cloud("copy_of_fragment.pcd", pcd)

Testing IO for point cloud ...
geometry::PointCloud with 113662 points.

True

print() can be used for displaying a summary of pcd.

By default, Open3D tries to infer the file type by the filename extension. Below is a list of supported point cloud file types.

Format	Description
xyz	Each line contains [x, y, z], where x, y, z are the 3D coordinates
xyzn	Each line contains [x, y, z, nx, ny, nz], where nx, ny, nz are the normals
xyzrgb	Each line contains [x, y, z, r, g, b], where r, g, b are in floats of range [0, 1]
pts	The first line is an integer representing the number of points. Each subsequent line contains [x, y, z, i, r, g, b], where r, g, b are in uint8
ply	See Polygon File Format, the ply file can contain both point cloud and mesh data
pcd	See Point Cloud Data

It’s also possible to specify the file type explicitly. In this case, the file extension will be ignored.

pcd = o3d.io.read_point_cloud("../../TestData/my_points.txt", format='xyz')

Mesh

This code below reads and writes a mesh.

print("Testing IO for meshes ...")
mesh = o3d.io.read_triangle_mesh("../../TestData/knot.ply")
print(mesh)
o3d.io.write_triangle_mesh("copy_of_knot.ply", mesh)

Testing IO for meshes ...
geometry::TriangleMesh with 1440 points and 2880 triangles.

True

Compared to the data structure of point cloud, mesh has triangles that define the 3D surface.

By default, Open3D tries to infer the file type by the filename extension. Below is a list of supported triangle mesh file types.

Format	Description
ply	See Polygon File Format, the ply file can contain both point cloud and mesh data
stl	See StereoLithography
obj	See Object Files
off	See Object File Format
gltf	See GL Transmission Format

Image

The code below reads and writes an image.

print("Testing IO for images ...")
img = o3d.io.read_image("../../TestData/lena_color.jpg")
print(img)
o3d.io.write_image("copy_of_lena_color.jpg", img)

Testing IO for images ...
Image of size 512x512, with 3 channels.
Use numpy.asarray to access buffer data.

True

The size of the image is readily displayed using print(img).