Hi Michael,
I have been giving the conic tool a solid personal walkthrough...

I have 2 basic questions (Well, one please inform me and one Gibson brain pick)

If I draw an ellipse and cut it in exact half, what do i call this?

For instance I can make the conic tool draw little parabolas at all points of the ellipse because I can use the tan's of the first 2 picks to get a point for the apex pick point... What would i do in the case of the half ellipse where both endpoints of the open half have "parallel tan's", so no converging point to choose?

The other brain pick was for fun to see if you had anything for me. I was looking into ways to find the foci of the ellipse... I ended up with the fastest "graphical way" (No formulas please) was to use a radius sphere at the semi major axis value and place its origin at the minor axis end point and foci are at intersection...

Is there any other "Trick" you have in the bag?

Thanks again!