Dave,

Sorry - I was out doing ‘Saturday Morning Things’ (here in South Eastern Florida where the temp is already about 73F…)

I’ll have to ‘re-wire’ my brain to think about ellipses & Grashopper rather than cycling …

BUT to answer your ‘quick’ questions (and yes, I’ll put your ‘ellipse.gh’ on my Windows / Rhino3D box and see what it tells me) - but your picture looks GOOD!!!

1.) I know that two tangents don’t uniquely identify a single ellipse segment - I don’t expect them to

2.) YES - the base-tangents are always vertical (“Z” axis parallel)

3.) YES - the apex tangent is always horizontal (and all the things that implies)

4.) YES the ‘base points’ are always on the same ‘elevation’ (on the same ‘plane’ (the x-y plane) - at least theoretically…

Your 'Video 3 / 5 where you move the outside curve(s) vertically (“Z” axis) would (most probably) never happen in a ‘real’ pottery-kiln - that ability (to move those sides (‘kiln-floor’)) might be of value from a ‘theoretical’ (geometry / mathematical) viewpoint, but I don’t see it happening for a ‘real’ kiln - On the other hand I am NOT an EXPERT in this realm and there might be a way this might be necessary…

in more ‘complex’ pottery-kilns, for a given ellipse the end-points (what you’ve labelled ‘base point’ in your colored-sketch) will always be co-planar (x-y plane) but different ellipses might be 1 foot or 2 feet ‘higher’ (that is they would be on another ‘x-prime’ / ‘y-prime’ plane that was parallel to the original x-y-plane

5.) YES the apex point is exactly in the middle…

I TRIED (in the past) to do the same thing with modeling pottery-kilns that I previously used while designing boat-hulls, which was to model (spend my ‘hours’) on ONLY HALF of the boat-hull; then doing a 'Transform => Mirror" command to get the other ‘half’ of the hull -

since the Apex Point (ellipse-middle) is always exactly in the middle, one could use the same technique to model a pottery-kiln as one has used to model a boat-hull - that is to really FOCUS one’s time on the 1/2 model and then ‘when all done’ to do the 'Transform=>Mirror" and make the other half…

the ‘REAL KEY’ for doing what you’ve defined for me VERY NICELY, and I need to work on this ONE THING, since you’ve shown me how GH can ‘automagically’ do a LOT of the work…

I NEED TO DO THIS:

in the ‘right’ view (viewing a kiln from the right side): (against a ‘y-z’ plane (what most could call a ‘vertical’ plane, I need to find a way to express the ‘apex-points’ (probably one every foot or so) as a ‘curve’ - it would normally be ‘about’ 4 feet high to start, then go to six feet high, then at the end ‘back’ - be about 3 feet high - that one curve, then defines the top-apex-point (apex tangent) for each ellipse…

with what you’ve done I need to FOCUS on using your Ellipse guide to do what it does best

I REALLY appreciate your support!!!

VERY Sincerely yours, Bill Schell