Voxelization Workshop

In this workshop we will learn how to voxelize a geometry and construct a lattice from it.

0. Initialization

Importing all necessary libraries and specifying the inputs

import os
import topogenesis as tg
import pyvista as pv
import trimesh as tm
import numpy as np

vs = 1.8
unit = [vs, vs, vs]
mesh_path = os.path.relpath('../data/compulsory_envelope.obj')

1. Input Mesh

# load the mesh from file
mesh = tm.load(mesh_path)
# Check if the mesh is watertight
print(mesh.is_watertight)

# convert trimesh to pv_mesh
def tri_to_pv(tri_mesh):
    faces = np.pad(tri_mesh.faces, ((0, 0),(1,0)), 'constant', constant_values=3)
    pv_mesh = pv.PolyData(tri_mesh.vertices, faces)
    return pv_mesh

# Visualize the mesh using pyvista plotter
#######

# initiating the plotter
p = pv.Plotter(notebook=True)


# adding the base mesh: light blue
p.add_mesh(tri_to_pv(mesh), color='white')

# plotting
p.show(use_ipyvtk=True)


#saving and plotting
png_path = os.path.relpath('../screenshots/mesh.png')
p.show(screenshot= png_path)

#start point array
mesh.vertices += np.array([0,0,-0.01])

2. Voxelize the Mesh

# initialize the base lattice
base_lattice = tg.lattice(mesh.bounds, unit=unit, default_value=1, dtype=int)

# check which voxel centroids is inside the mesh
interior_condition = mesh.contains(base_lattice.centroids)

# reshape the interior condition to the shape of the base_lattice
interior_array = interior_condition.reshape(base_lattice.shape)

# convert the interior array into a lattice
interior_lattice = tg.to_lattice(interior_array, base_lattice.minbound, base_lattice.unit)

print (enumerate(interior_lattice))

# convert trimesh to pv_mesh
def tri_to_pv(tri_mesh):
    faces = np.pad(tri_mesh.faces, ((0, 0),(1,0)), 'constant', constant_values=3)
    pv_mesh = pv.PolyData(tri_mesh.vertices, faces)
    return pv_mesh

# Visualize the voxelization using pyvista plotter
#####

# initiating the plotter
p = pv.Plotter(notebook=True)

# fast visualization of the lattice
interior_lattice.fast_vis(p)

# adding the base mesh: light blue
p.add_mesh(tri_to_pv(mesh), color='#abd8ff', opacity=0.1)

# plotting
p.show(use_ipyvtk=True)


#saving and plotting
png_path = os.path.relpath('../screenshots/ful_lattice.png')
p.show(screenshot= png_path)

3. Saving the lattice to CSV

csv_path = os.path.relpath('../data/voxelized_envelope_highres.csv')
interior_lattice.to_csv(csv_path)

Credits

__author__ = "Shervin Azadi"
_editor_ = "PROJECT APIDAE"
_editor_mentor_ = "Shervin Azadi"
__license__ = "MIT"
__version__ = "1.0"
__url__ = "https://github.com/shervinazadi/spatial_computing_workshops"
__summary__ = "Spatial Computing Design Studio Workshop on Voxelization"