def vector_poly_data(orig, vec):
"""Create a vtkPolyData object composed of vectors."""
# shape, dimension checking
if not isinstance(orig, np.ndarray):
orig = np.asarray(orig)
if not isinstance(vec, np.ndarray):
vec = np.asarray(vec)
if orig.ndim != 2:
orig = orig.reshape((-1, 3))
elif orig.shape[1] != 3:
raise ValueError('orig array must be 3D')
if vec.ndim != 2:
vec = vec.reshape((-1, 3))
elif vec.shape[1] != 3:
raise ValueError('vec array must be 3D')
# Create vtk points and cells objects
vpts = _vtk.vtkPoints()
vpts.SetData(_vtk.numpy_to_vtk(np.ascontiguousarray(orig), deep=True))
npts = orig.shape[0]
cells = np.empty((npts, 2), dtype=pyvista.ID_TYPE)
cells[:, 0] = 1
cells[:, 1] = np.arange(npts, dtype=pyvista.ID_TYPE)
vcells = pyvista.utilities.cells.CellArray(cells, npts)
# Create vtkPolyData object
pdata = _vtk.vtkPolyData()
pdata.SetPoints(vpts)
pdata.SetVerts(vcells)
# Add vectors to polydata
name = 'vectors'
vtkfloat = _vtk.numpy_to_vtk(np.ascontiguousarray(vec), deep=True)
vtkfloat.SetName(name)
pdata.GetPointData().AddArray(vtkfloat)
pdata.GetPointData().SetActiveVectors(name)
# Add magnitude of vectors to polydata
name = 'mag'
scalars = (vec * vec).sum(1)**0.5
vtkfloat = _vtk.numpy_to_vtk(np.ascontiguousarray(scalars), deep=True)
vtkfloat.SetName(name)
pdata.GetPointData().AddArray(vtkfloat)
pdata.GetPointData().SetActiveScalars(name)
return pyvista.PolyData(pdata)
def vector_poly_data(orig, vec):
"""Create a pyvista.PolyData object composed of vectors.
Parameters
----------
orig : numpy.ndarray
Array of vector origins.
vec : numpy.ndarray
Array of vectors.
Returns
-------
pyvista.PolyData
Mesh containing the ``orig`` points along with the
``'vectors'`` and ``'mag'`` point arrays representing the
vectors and magnitude of the the vectors at each point.
Examples
--------
Create basic vector field. This is a point cloud where each point
has a vector and magnitude attached to it.
>>> import pyvista
>>> import numpy as np
>>> x, y = np.meshgrid(np.linspace(-5,5,10),np.linspace(-5,5,10))
>>> points = np.vstack((x.ravel(), y.ravel(), np.zeros(x.size))).T
>>> u = x/np.sqrt(x**2 + y**2)
>>> v = y/np.sqrt(x**2 + y**2)
>>> vectors = np.vstack((u.ravel()**3, v.ravel()**3, np.zeros(u.size))).T
>>> pdata = pyvista.vector_poly_data(points, vectors)
>>> pdata.point_data.keys()
['vectors', 'mag']
Convert these to arrows and plot it.
>>> pdata.glyph(orient='vectors', scale='mag').plot()
"""
# shape, dimension checking
if not isinstance(orig, np.ndarray):
orig = np.asarray(orig)
if not isinstance(vec, np.ndarray):
vec = np.asarray(vec)
if orig.ndim != 2:
orig = orig.reshape((-1, 3))
elif orig.shape[1] != 3:
raise ValueError('orig array must be 3D')
if vec.ndim != 2:
vec = vec.reshape((-1, 3))
elif vec.shape[1] != 3:
raise ValueError('vec array must be 3D')
# Create vtk points and cells objects
vpts = _vtk.vtkPoints()
vpts.SetData(_vtk.numpy_to_vtk(np.ascontiguousarray(orig), deep=True))
npts = orig.shape[0]
cells = np.empty((npts, 2), dtype=pyvista.ID_TYPE)
cells[:, 0] = 1
cells[:, 1] = np.arange(npts, dtype=pyvista.ID_TYPE)
vcells = pyvista.utilities.cells.CellArray(cells, npts)
# Create vtkPolyData object
pdata = _vtk.vtkPolyData()
pdata.SetPoints(vpts)
pdata.SetVerts(vcells)
# Add vectors to polydata
name = 'vectors'
vtkfloat = _vtk.numpy_to_vtk(np.ascontiguousarray(vec), deep=True)
vtkfloat.SetName(name)
pdata.GetPointData().AddArray(vtkfloat)
pdata.GetPointData().SetActiveVectors(name)
# Add magnitude of vectors to polydata
name = 'mag'
scalars = (vec * vec).sum(1)**0.5
vtkfloat = _vtk.numpy_to_vtk(np.ascontiguousarray(scalars), deep=True)
vtkfloat.SetName(name)
pdata.GetPointData().AddArray(vtkfloat)
pdata.GetPointData().SetActiveScalars(name)
return pyvista.PolyData(pdata)