[D3D] Picking a line

Hey.
Turn the line into a rectangle if 2d, or a box then do pick.

Point: That's easy. Transform it into screen space, compare to mouse position. If distance is less than something (less than a pixel, for example), consider it picked.

Line: Transform both endpoints into screen space, use 'distance between point and line' calculation (google it) to find out how far the mouse position is from the line, and if close enough also check that it's not beyond the two endpoints (i.e., it's on the line segment).

I know this techniques,

But what if I want to select lines with a pick rectangle selection and one very long line crosses the rectangle without having a point in it.

Thanks again,

Alberto