File IO¶

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

Point cloud¶

The code below reads and writes a point cloud.

[2]:

print("Testing IO for point cloud ...")
sample_pcd_data = o3d.data.PCDPointCloud()
pcd = o3d.io.read_point_cloud(sample_pcd_data.path)
print(pcd)
o3d.io.write_point_cloud("copy_of_fragment.pcd", pcd)

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

[2]:

True

By default, Open3D tries to infer the file type by the filename extension. The following point cloud file types are supported:

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. The subsequent lines follow one of these formats: `[x, y, z, i, r, g, b]`, `[x, y, z, r, g, b]`, `[x, y, z, i]` or `[x, y, z]`, where `x`, `y`, `z`, `i` are of type `double` and `r`, `g`, `b` are of type `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.

[3]:

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

Mesh¶

The code below reads and writes a mesh.

[4]:

print("Testing IO for meshes ...")
knot_data = o3d.data.KnotMesh()
mesh = o3d.io.read_triangle_mesh(knot_data.path)
print(mesh)
o3d.io.write_triangle_mesh("copy_of_knot.ply", mesh)

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

[4]:

True

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

By default, Open3D tries to infer the file type by the filename extension. The following mesh file types are supported:

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`/`glb`	See GL Transmission Format

Image¶

The code below reads and writes an image.

[5]:

print("Testing IO for images ...")
image_data = o3d.data.JuneauImage()
img = o3d.io.read_image(image_data.path)
print(img)
o3d.io.write_image("copy_of_Juneau.jpg", img)

Testing IO for images ...
[Open3D INFO] Downloading https://github.com/isl-org/open3d_downloads/releases/download/20220201-data/JuneauImage.jpg
[Open3D INFO] Downloaded to /home/runner/open3d_data/download/JuneauImage/JuneauImage.jpg
Image of size 800x489, with 3 channels.
Use numpy.asarray to access buffer data.

[5]:

True

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

Both jpg and png image files are supported.