@Nausicaä The file you shared appears to be the same version as the one I originally shared. Please share your modified script with internalized geometry.
As mentioned,
Also note that if you plan to map this to a curved surface the
IsoTrim+BoxRectangleapproach will not work and need some proper adjustment.
There are many different approaches to UV divisions of curved surfaces, but the isocurves depend greatly on the nature of the geometry to map. See for example; 2d staggering circle pattern - #7 by Joseph_Oster
Without your target geometry, I can not help much in that regard.