Thanks! Using the @jfavre and @olesenm’s advice I was able to get this to work. I have included the XML text below in case anyone else needs to do this. I needed to add ‘Type=’ to the ‘Vert’ data arrays and include a ‘PointData’ section to get the values associated with the point coordinates:
<?xml version="1.0"?>
<VTKFile type="PolyData" version="0.1" byte_order="LittleEndian" header_type="UInt64">
<PolyData>
<Piece NumberOfPoints="8" NumberOfVerts="8">
<Points>
<DataArray type="Float64" Name="Coordinate_of_points" NumberOfComponents="3" format="ascii">
0 0 0
1 0 0
1 1 0
0 1 0
0 0 1
1 0 1
1 1 1
0 1 1
</DataArray>
</Points>
<PointData>
<DataArray type="Float64" Name="Value_at_point" NumberOfComponents="1" format="ascii">
0.6
1.1
1.9
0.1
0.9
1.2
1.3
0.3
</DataArray>
</PointData>
<Verts>
<DataArray type="Int32" Name="offsets">
1 2 3 4 5 6 7 8
</DataArray>
<DataArray type="Int32" Name="connectivity">
0 1 2 3 4 5 6 7
</DataArray>
</Verts>
</Piece>
</PolyData>
</VTKFile>
I’ve marked this one as the solution since it has the working XML text, but credit to @jfavre and @olesenm!