Mike Horvath <mik### [at] gmailcom> wrote:

> Since I'm trying to model ellipsoidal coordinate system, the formulas
> need to be parametric, so that I can make proper grid lines at the
> correct intervals and angles and so forth. You and Tor Olav did a great
> job of figuring out the method of creating offset surfaces of implicit
> functions. Would you mind trying the same for parametrics? Thanks.

Surely I'm missing something.
(It's likely - as it's Saturday morning, and I'm only 1 cup into it)

You, Mike Horvath, are mikh2161, posfan12 as well as (but not limited to)
SharkD.
The elliptic and hyperbolic curves in the Geogebra file were made by you.
(10 years ago)
When you click on the Geogebra file link, you get the drawing on the right, and
the formulas on the left.

So all you need to do is make the same thing in 3D - a series of nested shells
(with thickness)

Those shells are proportional, not constant-thickness, correct?
So they're just scaled versions of each other.
And ellipsoids are just scaled spheres.

Do you want the GRID, or do you want to be able to place "points" on the grid?
Are you using standard elliptic math, or some specialized geodectic system with
an equation that only you have worked out and know the form of?

Because you can mix isosurface shells and parametrically placed points.
The solution of the implicit and parametric equations are exactly the same.
They give you exactly the same set of points in space.


I have a hard time (efficiently) programming using a ouijaboard instead of a
keyboard, and the only chicken I have is in the freezer.
If I'm lucky, I likely have another 15 minutes free before RL starts pulling me
away.
Ready... set.... GO!

Fully stating the exact goal in no uncertain terms helps define what needs to be
done, so that the solution is the one desired, not one that's close, but still
completely useless.  You probably can't use a 2015 Toyota starter in a 1958
Ford, but it would take the same amount of effort to deliver you either part.

Perhaps you could freely share some completed SDL that's implementing the
solutions already given to you to shed some light on the mystery.
"I need to get from HERE to THERE, in order to do exactly THIS (and NOT _that_)"

Please, and Thank You.

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