Grasshopper

algorithmic modeling for Rhino

Hi Guys,

 

Is there any way to build a oval which we can control its three directions' dimentions?

 

thanks!

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Replies to This Discussion

I mean the 3d oval. not 2d..

use a Sphere and the Scale NU component

thanks, seems like this is the only way I can do it...

Aha, sorry, Im stupid, once we set up the sphere Dimention to 1 the scale is precise, thanks!!  

Just came across this searching with the same question. I'm pretty sure scaling a sphere yields an ellipsoid and not an ovoid.

What is  your definition of an Ovoid? I am not familiar with (nor can I find) any mathematical definition of an oval.

Assuming you just want an ellipsoid, the other answers work great.

Ovals and ellipses are superficially the same but different mathematically and in projection. An ellipse can be drawn with a pencil and two pin points connected by a string longer than their distance, whereas an oval is two pairs of circles trimmed tangent to one another. I was literally looking to reproduce an egg (oval comes from the Latin ovum) which is has only one axis of symmetry. Scaling a sphere won't produce an egg shape. I've been wrestling with ways to create a tangent arc between two circles (of different radii) but unfortunately the GH component only seems to yield concave tangent arcs. I'm not trying to be a wise-acre...just trying to draw an egg.
MKT,

Looks like what I was trying to do but the fairing btwn the spheres was inverted (concave). I was using the Tangent Arc Between Circles. Did you find a way of making that component do a convex arc or did you use some other way?

Hello Robert,

I had made this little script for a friend last year, using one of the equations off the internet, for egg-shape. It's not perfect since the base of the "egg" is flat (it was supposed to be an egg-shaped building), but maybe it is of some use to you?

Very elegant. Thank you Sridevi!

Its interesting that along with the egg formula (I didn't know there was one), there's also a drawing method similar to the classical ellipse method with a string, only with three pins instead of two. I found it here...

http://www.mathematische-basteleien.de/eggcurves.htm

Ah neat, then you can apply the method in Grasshopper to get the perfect curve and the perfect egg!

I vaguely recall seeing this webpage myself, though I didn't think to get the curve in this manner :-|

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