Hi hadri1,

> unluckily, i created the Cplane, but i am not able to snap onto the intersection
> between the Cplane and the line.

Your Cplane isn't working because you've got the "Align to objects" option turned off when you place the cplane onto the plane's corner point.



When this option is disabled then only the origin point of the cplane is modified and the x/y/z axis directions remain in world orientations.

To get your cplane intersection working you need to turn on the "Align to objects" option when setting the cplane so the z axis will be normal to the plane, like this:



If it looks like this (below) as in your video it still has world axis directions for the construction plane's x/y/z axes.



- Michael