les réponses de Michael qui montrent qu'il va falloir trouver une astuce s'il on veut vraiment utiliser la fonction "Flow"!
(du genre projeter sur un volume cible plus grand et faire une découpe et encore c'est pas gagné )

La 1ère avec mon exemple du dessus


Hi Pilou, for "Projective" mode, it's best if every single normal that goes out through the base surface intersects with a point on the target object.

If the target object is only the exact same size as the base object, it's easy for many rays to "miss" and not hit any result, and that will make for some unstable results like you show there.

So for your own example there, instead of making a small sphere fragment for the target object, make a full sphere object for the target object.

Basically with the regular non-projective mode, you do want a similar size between base and target surfaces. Projective mode is pretty different in how it works and it's better to have a larger target object (which can be a solid made up of multiple surfaces, projective mode doesn't need a single surface target like the texture mapping flow does), so that all shot rays intersect with the target instead of having some rays shoot out into empty space.

Hope that makes sense.

La 2ème avec le fichier des "5 objets"

another thing that's not good for projective mode is for the target surface to come to a very steep 90 degree angle with respect to the target surface, that makes it harder to intersect rays coming from the base surface in that steep area, in addition to a lot of rays missing.

Here's some visual description: