Hello,
I have an annoying problem that I can't seem to solve at all.
I am using a set of points (generated from ~50 streamlines) to generate a
surface that supposedly follows my magnetic fieldlines. I am using the
SurfaceReconstructionFilter to generate a ImageData set from which the
isosurface is generated. Then once I have the isosurface I extract the
PolyData for the surface and use the normals to generate a velocity
perpendicular to the surface.
The problem comes when I want to then colour the isosurface with the values
I have just calculated. I have tried to go back and find an attribute in
the ImageData set to set some scalar point data and use that to colour the
surface but nothing I try seems to work.
Here is the code snippet I am using:
#My magnetic field
>
> bfield = mlab.pipeline.vector_field(f.w_sac['b3'][cube_slice] * 1e3,
>
> f.w_sac['b2'][cube_slice] * 1e3,
>
> f.w_sac['b1'][cube_slice] * 1e3,
>
> name="Magnetic Field")
>
>
> #This uses a custom subclass of Streamline so I can manually set the seed
> points.
>
> field_lines = sStreamline(seed_points = np.array(seeds))
>
> bfield.add_child(field_lines)
>
>
> #Get the points from the streamlines
>
> f_lines = field_lines.outputs[0].points
>
> f_points = tvtk.PolyData(points=f_lines)
>
> #Create the surface
>
> sr =
> tvtk.SurfaceReconstructionFilter(input=f_points,sample_spacing=spacing)
>
> sr.update()
>
> #Add the surface to Mayavi
>
> tube = mlab.pipeline.surface(sr.output)
>
> tube.enable_contours=True
>
> tube.contour.auto_contours = False
>
> tube.contour.contours = [0.0]
>
>
> #Get and compute the normals
>
> tube_PD = tube.contour.outputs[0]
>
> norms = tvtk.PolyDataNormals()
>
> norms.input = tube_PD
>
> norms.compute_point_normals = True
>
> norms.flip_normals = True
>
> norms.update()
>
> normals = np.array(norms.output.point_data.normals)
>
> #Calculate the projection of V on the normal vector.
>
> vperp = []
>
> for i, perp in enumerate(normals):
>
> vperp.append(np.dot(perp, np.array([v3i[i],v2i[i],v1i[i]])))
>
> vperp = np.array(vperp)
>
>
> #Now I wish to colour tube with the vperp array.
>
Any suggestions would be greatly appreciated!
Thanks
Stuart
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