Hello,

I am new to VTK.

I want to print a list of vertices’ location and IDs from an imported mesh.

For a list of vertices, I have to loop “GetPoint(i)”…?

For a list of IDs, “GetPointIds” return the list of point ids, but how to print the list of IDs.

What I got is vtkIdList…

Besides, how to use “PrintSelf”?

# How to print a list of vertices' location and IDs using python?

**Wenye_He**(Wenye He) #1

**jfavre**(Jean M Favre) #2

It seems like you want a list of ids and coordinates as numpy arrays.

I would suggest the following:

from vtk.util import numpy_support

pd=mesh.GetPointData()

ida=pd.GetGlobalIds()

nida=numpy_support.vtk_to_numpy(ida)

coords = mesh.GetPoints().GetData()

ncoords = numpy_support.vtk_to_numpy(coords)

ncoords and nida are numpy arrays. easy to view on your terminal.

HTH

**Wenye_He**(Wenye He) #3

I did my work by loops. Thanks for your suggestion. I am doing point2point registration. I modify the arrange and locations of the points in numpy array and replace those of copy of target mesh. Is there any document of numpy_support for numpy_to_vtk?

**banesullivan**(Bane Sullivan) #4

PyVista might be a library worth checking out - it creates a streamlined interface to the VTK Python bindings making tasks like this way simpler:

```
import pyvista as pv
import numpy as np
# Load your file
mesh = pv.read('my_file.vtk')
# Access all the points
print(mesh.points)
```

Also note, we handle all the data conversions between VTK and NumPy for you. These can get complicated depending on your data type

```
assert isinstance(mesh.points, np.ndarray)
```

For the IDs, we preserve the order of all data from the underlying VTK data object. The IDs would be the index along the 0th axis of the `mesh.points`

numpy array:

```
ids = np.arange(mesh.n_points, dtype=int)
print(ids)
```