Hello Spharm-pdm experts,

I have a rather quick question about flipping in the ParaToSPHARMMeshCLP step (I am running everything via command line).

I see that the terminal prints the "BestFlip" for each subject. Most of my subjects have "BestFlip: 0,0" but others have different values for this parameter (e.g., "BestFlip: 1,5", "BestFlip: 2,4"). 

All of my subjects had their bionary hippocampal ROIs in the same orientation at the very start of my analysis. Does this imply that all subjects should have the same values for this BestFlip field?

Thanks!
Lara

Not necessarily, the flips are depending on how the program traverses/generates the initial mesh, which is deterministic. Butt even for similar shapes this may result in different mesh traversal (while parametrization orientation in 1D is unique, it is not for a 2D surface such as a mesh). So, you may end up with flips in the parametrization. This is why one supplies a flip template, i.e. to determine whether the spherical parametrization needs to be flipped, e.g. a flip of the north and south pole).


Martin

Thanks for the clarification!

Lara