scott <sco### [at] scottcom> wrote:

>
> That's exactly what I suggested in my post :-) Sorry if it wasn't clear.

Sorry; I was concentrating on Sam's post, and my mind went blank on everything
else  :-/

But unfortunately (maybe for both of us), the 'simpler' method, as I called it,
doesn't work. Actually, it *did* work in my initial test, but I didn't pay close
enough attention to what I was seeing.

I now realize what the problem is (and I should have remembered it, as it's
fooled me in the past): Trace's 'direction' vector is solely a *direction*; it
doesn't actually correspond to any particular point in space--like the end of
'line 1' in my example. It never changes. So by using this scheme and, for
example, varying trace's 'shoot-from' point but NOT its 'direction', the
direction it shoots in always remains 'parallel to itself', if that makes any
sense. Like your hand with a stiff finger pointing out, while moving the hand up
and down. So trace *might* hit the test cylinder--but that's an extremely
special case; and trace's returned result may not even correspond to the lines'
true intersection point (as I found out.)

So it seems that Sam's method is *definitely* the better one. ;-)

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