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.