`vtkImageCPRMapper` questions

Hi all,

I’m trying to use vtkImageCPRMapper to construct a panoramic projection for teeth, but I can’t get it to work.

I have a spline running through the volume. I’m visualizing it on the axial (transversal) plane:

I take points from that spline and their normals, and create a centerline polydata from them using this code:

    const centerline = vtkPolyData.newInstance();
    centerline.getPoints().setData(Float32Array.from(points), 3);

    const nPoints = points.length / 3;
    const lines = new Uint16Array(nPoints + 1);
    lines[0] = nPoints;
    for (let i = 0; i < nPoints; i++) lines[i + 1] = i;

        name: 'Orientation',
        numberOfComponents: 3, // vectors instead of matrices
        values: Float32Array.from(normals),

I then feed this centerline to a vtkImageCPRMapper like so:

    const cprMapper = vtkImageCPRMapper.newInstance();
    cprMapper.setBackgroundColor(255, 255, 0, 255);

I get this (yellow is the background):

And this if I use tangents as point orientations:

I’m not sure what I should give exactly as the orientation for the points in centerline. I saw in another post that they use mapper.setDirectionMatrix(...), but I’m not sure what to give it as value.

What should I put as orientations for the points in centerline? Or is there some settings that I should give to the mapper that I’m missing?

Any help would be greatly appreciated!