解决：open3d中Unable to cast Python instance to C++ type (compile in debug mode for details)

Posted 2021-10-11 沉迷单车的追风少年

项目场景： 

三维点云重建

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问题描述：

    pcd.points = o3d.utility.Vector3dVector(source_data)    # numpy.array转换成point cloud
RuntimeError: Unable to cast Python instance to C++ type (compile in debug mode for details)

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原因分析：

这个报错的表现意思是不能将Python实例转换成C++类型，需要你debug模式下详细查一查。

如果打开debug模式去查的话，半天又没了，还查不出来。坑得一批。

核心在于没有reshape！

将上面的一句代码：

source_data = source_data[:, 0:3]

改成：

source_data = source_data[:, 0:3].reshape(-1, 3)

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解决方案：

原先报错代码：

import numpy as np
import open3d as o3d

# filePath = './GEN_Ours_chair_1631677128/out.npy'
filePath = './GEN_Ours_airplane_1631630214/out.npy'
np.set_printoptions(suppress=True) # 取消默认科学计数法，open3d无法读取科学计数法表示

loadData = np.load(filePath)
print("----type----")
print(type(loadData))
print("----shape----")
print(loadData.shape)
print("----data----")
print(loadData)

# source_data = np.load(filePath)[:,0:3][:,0:3]
point_cloud = o3d.geometry.PointCloud()
source_data = np.load(filePath)
# source_data = np.squeeze(source_data)
print(source_data.shape)
# print(source_data)
pcd = o3d.geometry.PointCloud()
# source_data = source_data[:, 0:3].reshape(-1, 3)
source_data = source_data[:, 0:3]
pcd.points = o3d.utility.Vector3dVector(source_data)    # numpy.array转换成point cloud
o3d.visualization.draw_geometries([pcd])

print("finish!")

改正后：

import numpy as np
import open3d as o3d

# filePath = './GEN_Ours_chair_1631677128/out.npy'
filePath = './GEN_Ours_airplane_1631630214/out.npy'
np.set_printoptions(suppress=True) # 取消默认科学计数法，open3d无法读取科学计数法表示

loadData = np.load(filePath)
print("----type----")
print(type(loadData))
print("----shape----")
print(loadData.shape)
print("----data----")
print(loadData)

# source_data = np.load(filePath)[:,0:3][:,0:3]
point_cloud = o3d.geometry.PointCloud()
source_data = np.load(filePath)
# source_data = np.squeeze(source_data)
print(source_data.shape)
# print(source_data)
pcd = o3d.geometry.PointCloud()
source_data = source_data[:, 0:3].reshape(-1, 3)
# source_data = source_data[:, 0:3]
pcd.points = o3d.utility.Vector3dVector(source_data)    # numpy.array转换成point cloud
o3d.visualization.draw_geometries([pcd])

print("finish!")

运行效果：

 这是一个飞机啊，有多少人能看出来。。。。。。。。