Sorry! I m not able to try to write the formula because i don’t know how to write with the computer the symbol “racine carrée” that we have here, as you can see here on the formula i download in jpeg. Can you please help me? Thanks so much!

Thanks so much!

Here, it is the file, i try to do the formula, but it seems i made mistakes.

I know that the z: cv, c*u, does’nt have input and output, but i tried to do input, and output, and nothing appears. Here, i have something… but wrong i know.
Other thing is that formula is:
x(u,v)= a squared (1+u*u)

*cos(v)*

y(u,v)= b squared (1+uu)

y(u,v)= b squared (1+u

*sin(v)*

z(u,v)= cu

z(u,v)= c

and i don’t know how to “translate” a and b. I dEllipticHyperbol.gh (10.9 KB)

I did like it would be “1”, but shure it’s more complex…

So, thanks so much if you can’t help me!

`sqrt`

is Square Root, not square. To square something called `a`

you either write `a*a`

, `a²`

, `a^2`

or `Pow(a, 2)`

.

If your expression need to access values `u`

, `v`

, and `a`

, then your expression object needs to have those three inputs. You can add (and remove) inputs by zooming in on the expression component and clicking on the (+) signs. You can rename inputs via their context menu. So add a third input called `a`

to your expression, and type:

```
a * a * (1 + u * u) * Cos(v)
```

or

```
a² * (1 + u²) * Cos(v)
```

Hi David!

Thanks so much!

The formula, as we can see on my first post here is:

x(u,v)= a squared root of (1+u*u)*cos(v)
y(u,v)= b squared root of (1+u*u)

*sin(v)*

z(u,v)=cu

z(u,v)=c

Now i m try to do what you say!

Thanks so much!

I didn’t read all the way back to the beginning, I just responded to your last entry which read ‘squared’ not ‘square root’.

The correct GH way of writing the equation from your mathworld screenshot is:

```
a * Sqrt(1 + u * u) * Cos(v)
```

Hi David!

Thanks so much!

Now, i tried to do what i think it was good, but it’s wrong… Here you have the screenshot:

Hi David!

thanks so much!

Now i think it’s better… but i think it’s not the result i should have, it’s not an elliptic hyperboloide, and i have only points… but better…

Why mess around with interpolating points when you can generate a mathematically exact hyperboloid using NURBS?

Check out this article:

http://www.danieldavis.com/how-to-draw-a-hyperboloid/

One nice thing to realise about the formula is that for any given parameter u, the Z coordinate is fixed and the X and Y coordinates describe an ellipse of the form

x = a'*cos(v)

y = b'*sin(v)

This allows you to factor out the variable v entirely, and end up with a smoother and simpler surface:

EllipticHyperbol3.gh (10.5 KB)

(edited from HS_Kim’s answer)

Hi! Thanks so much!

Hi Joseph!

Thanks so much! As i can, i try it!

Hi!

Thanks so much@:

HS_Kim

Joseph_Oster

qythium

I try it as soon as i can!