# Intersecting Vectors of Vectors and Plane

Hi together,

Just a short question: a have a set of vectors and a plane. The plane is intersecting with some vectors in the set. What I want is a list with intersecting vectors?

How can this be done?

Hi @birkenholzstuhl
You can’t intersect vectors with planes as vectors don’t define a position in space just a direction.
What you can do though is creating lines from your anchor points and vectors using `LineSDL` and intersect those lines with your plane

Hope this helps

Thanks Lando,

that is what I have also done so far, however I get the intersecting point of every line not online the lines that are going through the pane. I want a list with only the lines that are touching the plane. Did I miss something?

By definition a “Line” is infinite so it always intersect with a plane (if not parallel to it).
What you might want to do is to create a Line-curve with pseudo infinite length (SDL with L=99999) and do Plane-Curve intersect instead.
Or you can use “IsoVist” component which take as inputs lines and use them as rays.

Edit:
For non native english , like me, this is a case when english is “not clear”… a line usually is translated for a simple finite object (even outside rhino/CAD context), but sometime it become an infinite one.
In italian “linea” for the “straight line from A to B” but we also have “retta” for the infinite straight one aka “straight line”; and “semi-retta” for the half one, aka “ray” or “half-line”.

In grasshopper a “Line” is almost always used as “Line-Curve” (a finite object) and only in the intersection tab used as the infinite object “Straight line”.

Use PCX (Curve | Plane) instead of PLX (Line | Plane):

crv_plane_2019Jul11a.gh (12.0 KB)

You want the yellow points from PCX, not the red points from PLX. As @maje90 explained, lines are considered infinitely long for intersection purposes, which can be very useful. But in this case, you want to treat them like curves instead.

That solved my problem. Thank you!