Unable to render a StructuredGrid source using ProgrammableSource filter

[jmb64 (Jean-Marc Belanger)]

As an exercise (being new to Paraview-VTK) I tried to use this piece of python code
as a ProgrammableSource (Output Type set to StructuredGrid) in PARAVIEW 5.13.
I am trying to model two concentric spherical surface (radius values of 1 and 2).
I don’t know how to make those points (scalar “Radius”) magically appear in the RenderView !
A similar exercise but setting the Output Type to PolyData works fine (Glyph filter following the
ProgrammableSource is needed though).

import numpy as np
from vtkmodules.vtkCommonCore import vtkPoints, vtkDoubleArray
from vtkmodules.vtkCommonDataModel import vtkStructuredGrid

Define grid dimensions

n_theta = 18 # Number of points along theta
n_phi = 36 # Number of points along phi
radii = [1.0, 2.0] # Two radial layers

Initialize points and scalars

points = vtkPoints()
scalars = vtkDoubleArray()
scalars.SetName(“Radius”) # Scalar for radius-based coloring

Fill points in spherical coordinates and convert to Cartesian

for r in radii:
for theta_idx in range(n_theta):
theta = theta_idx * np.pi / (n_theta - 1)
for phi_idx in range(n_phi):
phi = phi_idx * 2 * np.pi / (n_phi - 1)

        # Spherical to Cartesian conversion
        x = r * np.sin(theta) * np.cos(phi)
        y = r * np.sin(theta) * np.sin(phi)
        z = r * np.cos(theta)
        
        points.InsertNextPoint(x, y, z)
        scalars.InsertNextValue(r)  # Radius as a scalar value

Create the structured grid and assign points and scalars

output.SetDimensions(n_theta, n_phi, len(radii))
output.SetPoints(points)
output.GetPointData().SetScalars(scalars

Rendering for the Output Type PolyData gives this :

UPDATE: Thanks to Jean M. Favre suggestion in this 2019 post …

Problem displaying Structured Grid when loading from Programmable Source

Hi, I am trying to make a file reader for a structured grid file that is not currently supported, but I can read it into a numpy array. To start simple I tried to make a programmable source which just creates a cube (Output Data Set Type: vtkStructuredGrid) import numpy as np # Cube xs = np.linspace(0,1,10) ys = np.linspace(0,1,10) zs = np.linspace(0,1,10) dims = [len(xs),len(ys),len(zs)] # Setting S-Grid extent output.SetExtent([0,len(xs)-1,0,len(ys)-1,0,len(zs)-1]) # VTK points points =…

ProgrammableSource using StructuredGrid Output Type is working but …

I guess, the question that comes to my mind now is

1. Why in the PolyData Output type case,references to the vtk pipeline mechanics are not necessary ( i.e. commands like executive.GetOutputInformation(0), …,) ?

2. Also, there seems to have synchronization or communication issue (client-server). The default Outline rendering does show only after pushing the Apply button a second time … Some some of update mechanism seems to be triggered then and the Outline appears.

But I’m way over my head here … speculating on something I barely know
Lots of fun ahead !