What is the name of the shape of a go stone ?

[oca]

Does anyone knows the name of the shape of a go stone ?
Thanks

[oca]

Oh thanks,... "biconvex" that may be a good starting point for me... I'm trying to draw a stone using the javascript library
"THREE.js", but don't really know where to start... There are examples with cube and sphere, but none with go stones

[Uberdude]

Traditional biconvex stones are fairly close to an ellipsoid, though they may have a more pronounced 'lip' on the equator.

[tj86430]

Traditional biconvex stones are fairly close to an ellipsoid

And a specific kind of ellipsoid: oblate spheroid

[oca]

Whoaw... what a lovely name...
unfortunatly, there are no ready to use OblateSpheroidGeometry in three.js so for now I will use just Sphere and scale it's z axis... which should be the ellipsoid right ?

Maybe I should post that in Computer GO topic but here is what I get now :

http://www.gocdf.ch/gobook/3D/stone.html

[gowan]

Lenticular?

[DrStraw]

Lenticular?

Can't lenticular also refer to a concave lens?

[Boidhre]

Lenticular?

Can't lenticular also refer to a concave lens?

In maths or English? In maths, as far as I can remember lens in the sense of shape only is used for 2d convex-convex shapes and lenticular for a 3d rotation of that shape. In English the usage isn't as precise as that and you have lens referring to convex-concave shapes and others.

Go stones aren't lenticular for the reasons Uberdude said above about elipsoids which lenticular objects are a subset of iirc (many years since I studied this stuff so I could be wrong).

[DrStraw]

Lenticular?

Can't lenticular also refer to a concave lens?

In maths or English? In maths, as far as I can remember lens in the sense of shape only is used for 2d convex-convex shapes and lenticular for a 3d rotation of that shape. In English the usage isn't as precise as that and you have lens referring to convex-concave shapes and others.

Go stones aren't lenticular for the reasons Uberdude said above about elipsoids which lenticular objects are a subset of iirc (many years since I studied this stuff so I could be wrong).

Well, I thought this was a thread about an English word.

[Boidhre]

Well, I thought this was a thread about an English word.

The discussion has been about elipsoids and oblate spheroids, was going with the flow.

[gowan]

Lenticular?

Can't lenticular also refer to a concave lens?

Dictionary definition: having the shape of a double-convex lens.

The second meaning is having the shape of a lens which, as you say, might be concave.

[John Fairbairn]

Well, I thought this was a thread about an English word.

I want to agree, having, possibly like you, been brought up in a world where four hanks make a spangle, but the real words traditionally used to describe stone shapes are Japanese: kamaboko, (soroban) abacus bead and Honinbo.

The fact that the abacus bead stone shape resembles no abacus bead I have ever seen just adds to its charm.

[Bill Spight]

Well, I thought this was a thread about an English word.

I want to agree, having, possibly like you, been brought up in a world where four hanks make a spangle, but the real words traditionally used to describe stone shapes are Japanese: kamaboko, (soroban) abacus bead and Honinbo.

The fact that the abacus bead stone shape resembles no abacus bead I have ever seen just adds to its charm.

I does kind of look like the plastic beads of a cheap soroban I used to have. But not like those of the classier, wooden sorobans I have seen.