Mimicking a Ray with a Line

So I'm experimenting with a ray – attempting to detect when one model (call it Model A) ceases to be above another (Model B).  I am casting a vertical ray (I think) from A and can detect when that ray intersects with B; however, when A ceases to be above B the findpick still reports that the ray from A is intersecting with B (and strangely, the location of A reports that its still above B no matter how far I take it from B).  It's very confusing, but I think that I can figure out what's happening if I could see what this ray is actually doing.  So, my question is:

How does one go about drawing a line that exactly mimics a ray that has been cast?

I feel silly now.

Something like this can be used:

Vector3f[] vertices = new Vector3f[2];

vertices[0] = new Vector3f(-61f, 6.5f, 981f); // start point; ray's origin

vertices[1] = new Vector3f(0f,-1f,0f);  // end point; ray's direction using additional line segments if necessary

locLine = new com.jme.scene.Line("newline", vertices, null, null, null);