Thank you, AlexC, for the file.
Projecting is based on the "vertices/points only, which indicates the first tip, more points. Here are editable points, not just internmediadiate points. (Curent State to object, to convert intermediate points to editable points.
The Projection method used here is Spherical, which means points are moved to the axis until they hit a surface, leading to results that might not look logical, given anything wrapped around the two frame sides. To stop the points being only projected to the "tubes of the frame, I have introduced a little cube to stop the projection. The cube is no longer needed, except if you like to project a Rail spline, as used in the video, then the cube can go.
Anything else is as in the video clip.
Let me know how that works for you.
Here is the file back:
https://stcineversityprod02.blob.core.windows.net/$web/Cineversity_Forum_Support/2024_PROJECTS_DRS/20241113_CV4_2025_drs_24_MOsp_21.c4d.zip
Cheers