o-voxel/examples/mesh2ovox.py

import torch
import o_voxel
import utils

RES = 512

asset = utils.get_helmet()

# 0. Normalize asset to unit cube
aabb = asset.bounding_box.bounds
center = (aabb[0] + aabb[1]) / 2
scale = 0.99999 / (aabb[1] - aabb[0]).max()     # To avoid numerical issues
asset.apply_translation(-center)
asset.apply_scale(scale)

# 1. Geometry Voxelization (Flexible Dual Grid)
# Returns: occupied indices, dual vertices (QEF solution), and edge intersected
mesh = asset.to_mesh()
vertices = torch.from_numpy(mesh.vertices).float()
faces = torch.from_numpy(mesh.faces).long()
voxel_indices, dual_vertices, intersected = o_voxel.convert.mesh_to_flexible_dual_grid(
    vertices, faces,
    grid_size=RES,                              # Resolution
    aabb=[[-0.5,-0.5,-0.5],[0.5,0.5,0.5]],      # Axis-aligned bounding box
    face_weight=1.0,                            # Face term weight in QEF
    boundary_weight=0.2,                        # Boundary term weight in QEF
    regularization_weight=1e-2,                 # Regularization term weight in QEF
    timing=True
)
## sort to ensure align between geometry and material voxelization
vid = o_voxel.serialize.encode_seq(voxel_indices)
mapping = torch.argsort(vid)
voxel_indices = voxel_indices[mapping]
dual_vertices = dual_vertices[mapping]
intersected = intersected[mapping]

# 2. Material Voxelization (Volumetric Attributes)
# Returns: dict containing 'base_color', 'metallic', 'roughness', etc.
voxel_indices_mat, attributes = o_voxel.convert.textured_mesh_to_volumetric_attr(
    asset,
    grid_size=RES,
    aabb=[[-0.5,-0.5,-0.5],[0.5,0.5,0.5]],
    timing=True
)
## sort to ensure align between geometry and material voxelization
vid_mat = o_voxel.serialize.encode_seq(voxel_indices_mat)
mapping_mat = torch.argsort(vid_mat)
attributes = {k: v[mapping_mat] for k, v in attributes.items()}

# Save to compressed .vxz format
## packing
dual_vertices = dual_vertices * RES - voxel_indices
dual_vertices = (torch.clamp(dual_vertices, 0, 1) * 255).type(torch.uint8)
intersected = (intersected[:, 0:1] + 2 * intersected[:, 1:2] + 4 * intersected[:, 2:3]).type(torch.uint8)
attributes['dual_vertices'] = dual_vertices
attributes['intersected'] = intersected
o_voxel.io.write("ovoxel_helmet.vxz", voxel_indices, attributes)