How to create line through any plane, one point and parallel xy plane

[toantit1311]

Hi guys
I have any plane (rectangle) and one point into this plane
I want to create red line as picture and parallel xy plane
Thanks you very much

[Ewan_Opie]

So just to clarify, you are looking for the horizontal Plane.AtPoint where the Geometry.Intersect happens? To create a red Line.ByStartAndEndpoint

Can you provide an example of what you have tried so far?

[toantit1311]

Thank you for your clear instructions, I have completed it

[Ewan_Opie]

Glad to hear Any chance of posting a screenshot of the completed graph for the benefit of future topic viewers?

[toantit1311]

Of course, this is script I carried out
Thank you and hope will be given your support in next time