openmesh基础操作 numpy关于向量的运算

环境：python3.7
第三方库：openmesh、numpy

import openmesh as om

# 读取模型
mesh = om.read_trimesh(r'D:\Desktop\bunny.off')
# 保存模型
om.write_mesh( r'D:\Desktop\bunny1.off', mesh)

# 获取顶点、边、面的总数
print('顶点总数：', mesh.n_vertices())
print('面总数  ：', mesh.n_faces())
print('边总数  ：', mesh.n_edges())

顶点总数： 953
面总数  ： 1902
边总数  ： 2853

# 遍历所有的顶点，获取每个vertex的坐标
for vertex in mesh.vertices():
    print('顶点的数据类型：', type(vertex), '顶点坐标：', mesh.point(vertex), '顶点坐标的数据类型', type(mesh.point(vertex)))
    break
# 遍历所有的边和面
for edge in mesh.edges():
    print(type(edge))
    break
for face in mesh.faces():
    print(type(face))
    break

顶点的数据类型： <class 'openmesh.VertexHandle'> 顶点坐标： [-5.00492001 -7.67860889 -0.35177901] 顶点坐标的数据类型 <class 'numpy.ndarray'>
<class 'openmesh.EdgeHandle'>
<class 'openmesh.FaceHandle'>

半边结构
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# 半边结构
# 遍历每一条半边 获取每个半边的起点和终点 获取半边周围的元素
for halfedge in mesh.halfedges():
    fvertex = mesh.from_vertex_handle(halfedge); tvertex = mesh.to_vertex_handle(halfedge)
    print(type(halfedge), '半边的起点和终点：', mesh.point(fvertex), mesh.point(tvertex))
    print(' '*33, '半边对应的面：', mesh.face_handle(halfedge))
    print(' '*33, '半边的下一条半边：', mesh.next_halfedge_handle(halfedge))
    print(' '*33, '半边相对的半边：', mesh.opposite_halfedge_handle(halfedge))
    break

<class 'openmesh.VertexHandle'> 顶点的坐标： [-5.00492001 -7.67860889 -0.35177901]
<class 'openmesh.HalfedgeHandle'> 半边的起点和终点： [-4.35409498 -7.676548   -0.610264  ] [-4.35129881 -7.65309906  1.08651805]
                                  半边对应的面： <openmesh.FaceHandle object at 0x000001C02703C308>
                                  半边的下一条半边： <openmesh.HalfedgeHandle object at 0x000001C02703C308>
                                  半边相对的半边： <openmesh.HalfedgeHandle object at 0x000001C026792180>
<class 'openmesh.EdgeHandle'>
<class 'openmesh.FaceHandle'>

# 邻域遍历
for vertex in mesh.vertices():
    # 遍历顶点周围的1-邻域面
    for face in mesh.vf(vertex):
        print(face)
    print('1-邻域面的个数：', sum(1 for _ in mesh.vf(vertex)))
    # 遍历顶点周围的1-邻域顶点
    for vertex in mesh.vv(vertex):
        print(vertex)
    print('1-邻域顶点的个数：', sum(1 for _ in mesh.vv(vertex)))
    break
for face in mesh.faces():
    # 遍历面周围的1-邻域顶点和边
    for v in mesh.fv(face):
        print(v)
    for e in mesh.fe(face):
        print(e)
    break

<openmesh.FaceHandle object at 0x000001C027379378>
<openmesh.FaceHandle object at 0x000001C0273797D8>
<openmesh.FaceHandle object at 0x000001C027379378>
<openmesh.FaceHandle object at 0x000001C0273797D8>
<openmesh.FaceHandle object at 0x000001C027379378>
<openmesh.FaceHandle object at 0x000001C0273797D8>
1-邻域面的个数： 6
<openmesh.VertexHandle object at 0x000001C027379378>
<openmesh.VertexHandle object at 0x000001C027379308>
<openmesh.VertexHandle object at 0x000001C027379378>
<openmesh.VertexHandle object at 0x000001C02679CCA8>
<openmesh.VertexHandle object at 0x000001C02679C4C8>
<openmesh.VertexHandle object at 0x000001C02679CCA8>
1-邻域顶点的个数： 5
<openmesh.VertexHandle object at 0x000001C02679CF80>
<openmesh.VertexHandle object at 0x000001C026FF03E8>
<openmesh.VertexHandle object at 0x000001C02679CF80>
<openmesh.EdgeHandle object at 0x000001C026FF0148>
<openmesh.EdgeHandle object at 0x000001C026FF0298>
<openmesh.EdgeHandle object at 0x000001C026FF0378>

# 计算顶点和面的法向量
for f in mesh.faces():
    print(mesh.normal(f))
    break
for v in mesh.vertices():
    print(mesh.normal(v))
    break

[2.12199579e-314 0.00000000e+000 4.54540394e-321]
[2.12199579e-314 0.00000000e+000 4.68374232e-321]

numpy中关于向量的各种操作

import numpy as np

a = 1.0; b = 2.0
print(a,b)
print(a/b)
print(np.sqrt(b))
print(np.cos(-1))
print(np.sin(30.0/180.0*np.cos(-1)))
print('-'*50)
a = np.array([1.0, 0.0, 5.0]); b = np.array([1.0, 0.0, 3.0])
print('a=', a, 'b=', b)
print('a+b=', a+b)
print('向量点乘（内积）和叉乘（外积、向量积')
c = np.cross(a,b)
d = np.cross(b,a)
print('a cross b=', c)
print('b cross a=', d)
print('a dot b =', np.dot(a,b), a.dot(b), (a*b).sum())  # 点乘有很多种求法
print('向量a的长度=', np.linalg.norm(a), np.sqrt(a.T.dot(a)))
print('向量a的单位向量=', a/(np.linalg.norm(a)))
print('向量a和b的夹角余弦=', a.dot(b)/(np.linalg.norm(a) * np.linalg.norm(b)))

1.0 2.0
0.5
1.4142135623730951
0.5403023058681397
0.08992872947650446
--------------------------------------------------
a= [1. 0. 5.] b= [1. 0. 3.]
a+b= [2. 0. 8.]
向量点乘（内积）和叉乘（外积、向量积
a cross b= [0. 2. 0.]
b cross a= [ 0. -2.  0.]
a dot b = 16.0 16.0 16.0
向量a的长度= 5.0990195135927845 5.0990195135927845
向量a的单位向量= [0.19611614 0.         0.98058068]
向量a和b的夹角余弦= 0.9922778767136677