OK ! it is working.
My initial neeed was to move the point in the plane orthogonal to the X axis but without need to create an actual plane object.
Creating a CPlane is ok but using the "use object orientation" is not the solution for me because i don't want to add a plane object.
But as you will see in the "2025-12-14_09h34_28" video, it is possible to make in work without using this option if you manually change the z axis.


the process would be :
1 : create a Cplane at the selected point
2 : move the Z axis to the direction on the plane normal
3 : use the move function and now the CPlane In works.
4 : reset Cplane when you are done.

i think the process could be improved.

without adding a displacement gizmo, i think that if you can activate the CPlane intersection on the 3 standard planes [ (x,y) (y,z) and (x,z) ] and not only the (x,y) plane.
If you wand to limit the computation power, you can limit this computation to the object that the user is hovering onto. (so with the "on" snapping status)

This way you won't need to manually move the Z axis. and with 2 shortcut script if would be done !

in scripting :
how do you create the frame at the selected point and then reset when it is done.

For now i will definitely go with your solution.

Thank you again Michael.