401: Mesh sampling

This tutorial demonstrates how to:

• Use the Easy3D SurfaceMeshSampler class to sample points from a surface mesh.

• Visualize the original surface mesh and the sampled point cloud side-by-side using Easy3D’s MultiViewer.

The sampling process generates a near-uniform distribution of points over the surface of the mesh.

Sampled point cloud with 20000 points.

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# sphinx_gallery_thumbnail_path = '_static/sphx_glr_tutorial_401_mesh_sampler_thumb.png'

# -------------------------------------------------------------------------------
# Adding Easy3D Python Bindings to the System Path
# -------------------------------------------------------------------------------
# This is required if the bindings are not installed via `pip` but are located in
# a local build directory. For building and installing Python bindings of Easy3D,
# please refer to: https://github.com/LiangliangNan/Easy3D/blob/main/README.md
# -------------------------------------------------------------------------------
import sys
sys.path.append("../../cmake-build-release/lib/python")  # Update this path to point to your Easy3D build directory.

# Import the Easy3D library for 3D visualization and processing.
import easy3d

# Easy3D must be initialized before use.
easy3d.initialize(False)

# -----------------------------------------------------------------------------
# Setting Up the Multi-View Viewer
# -----------------------------------------------------------------------------
# See detailed explanations in "python/tutorials/tutorial_202_multiviewer.py"

# Create a MultiViewer instance with 1 row and 2 columns.
viewer = easy3d.MultiViewer(1, 2, "Easy3D Viewer - Mesh sampling")

# -----------------------------------------------------------------------------
# Loading the Surface Mesh
# -----------------------------------------------------------------------------
# Load the Bunny surface mesh from a file. Ensure the file path is correct.
mesh = viewer.add_model(easy3d.resource_directory() + "/data/bunny.ply")
# Assign the surface mesh to the left view (row=0, column=0).
viewer.assign(0, 0, mesh)

# -----------------------------------------------------------------------------
# Sampling Points from the Surface Mesh
# -----------------------------------------------------------------------------
# Use the `SurfaceMeshSampler` class to sample points from the mesh surface.
# The sampling process generates a near-uniform distribution of points.

# Perform the sampling. 20000 is the desired number of points to sample.
point_cloud = easy3d.SurfaceMeshSampler.apply(mesh, 20000)

# Print the number of sampled points.
print(f"Sampled point cloud with {point_cloud.n_vertices()} points.")

# Add the sampled point cloud to the viewer and assign it to the right view (row=0, column=1).
viewer.add_model(point_cloud)
viewer.assign(0, 1, point_cloud)

# Add instructions for the viewer (optional).
viewer.set_usage("",
    "Left view: Original mesh\n"
    "Right view: Sampled point cloud"
)

# The bunny model included in Easy3D has a per-face scalar property, which will be rendered by
# default. To better reveal the effect of sampling, let's show the bunny with a uniform color.
surface = mesh.renderer().get_triangles_drawable("faces")
surface.set_coloring_method(easy3d.State.UNIFORM_COLOR)  # Set uniform color rendering.

# Set the camera view direction and up vector for a better view position.
viewer.camera().setViewDirection(easy3d.vec3(0, 1, 0))   # Set the view direction.
viewer.camera().setUpVector(easy3d.vec3(0, 0, 1))        # Set the up vector.

# Launch the viewer.
viewer.run()