Hi!

From the topic i create about how to copy and paste a mathematic formula in GH, i tried, to do the same for the formula of an elliptic hyperboloid.

But, as i give here the formula, i don’t know, because we have two others parametres: a, and b. And i don’t know how to interprate this.

Other studid question, is, i don’t know how to write the mathematic symbol that we call in french “racine carrée de”, ou “radical de”.

Here i give you the formula.

I don’t know i you have solution. Thanks so much!

# Create an Elliptic Hyperboloid from the matematic formula

**kostaldeak**(Kostaldeak) #1

**kostaldeak**(Kostaldeak) #2

I think the basis is what i did

with the tutorial i did on youtube, but, all the difficultie is in the maner of reinterpreting the formula here!**tim.stark**(Tim Stark) #3

As I mentioned on your other two threads. Post your file and don’t create 3 threads for nearly the same question.

**kostaldeak**(Kostaldeak) #5

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!

**kostaldeak**(Kostaldeak) #7

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!

**DavidRutten**(David Rutten) #8

`sqrt`

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

you either write `a*a`

, `a²`

, `a^2`

or `Pow(a, 2)`

.

**DavidRutten**(David Rutten) #9

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)
```

**kostaldeak**(Kostaldeak) #10

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!

**DavidRutten**(David Rutten) #11

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)
```

**kostaldeak**(Kostaldeak) #12

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:

**kostaldeak**(Kostaldeak) #13

And the new file i modified… but it 's wrong…EllipticHyperbol2.gh (10.2 KB)

**kostaldeak**(Kostaldeak) #15

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…

**kostaldeak**(Kostaldeak) #17

and the new file is here,

Thanks so much! EllipticHyperbol2.gh (10.0 KB)

**qythium**(qythium) #18

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/