# Oblique Cone

jorge geraldes shared this question 7 years ago

Hi

How can construct a oblique cone?

Thank´s

Jorge Geraldes 1

Hi,

with surface :

Surface[x(C) u + (1 - u) x(A) + r (1 - u) cos(v), y(C) u + (1 - u) y(A) + r (1 - u) sin(v), z(C) u + (1 - u) z(A), u, 0, 1, v, 0, 2 pi]

See list of circles :

x(C) u + (1 - u) x(A) = x(center)

y(C) u + (1 - u) y(A) = y(center)

z(C) u + (1 - u) z(A) = z(center)

r (1 - u) = radius

cos(v) and sin(v) make circle.

https://ggbm.at/1389075 1

hello

i hoped c(2) is a point. is it possible?

c(t)=circle[A,B,C]

saludos  1

hello again

a question about the notation: what notation will progress?

create a circle A,B in planeXY then up and down B the notation change

saludos 1

Hi,

The reason for this is:

* there is no cartesian equation for conics in 3D, so we provide parametric equation

* on our todo list: possibly switch from paramatric to cartesian (when possible) as it's possible for points

Cheers,

Mathieu 1

hello

i hoped c(2) is a point. is it possible?

c(t)=circle[A,B,C]

saludos

saludos 1

Does Point[c,2] work? 1

hello

Does Point[c,2] work?

sorry,no

when i saw c(t)=( , , ) I had an illusion during some seconds: c(t):ℝ--------->ℝ³, then I could define d(t,u):ℝ²------->ℝ³

naturally i have tried

Surface[(1 - u) x(D) + u x(Point[c, t]), (1 - u) y(D) + u y(Point[c, t]), (1 - u) z(D) + u z(Point[c, t]), u, 0, 1, t, 0, 6.28319]

and naturally it does not work.

saludos 2

Hello mathmagic,

naturally i have tried

Surface[(1 - u) x(D) + u x(Point[c, t]), (1 - u) y(D) + u y(Point[c, t]), (1 - u) z(D) + u z(Point[c, t]), u, 0, 1, t, 0, 6.28319]

and naturally it does not work.

because surface command doesn't accept commands GGB, just the math functions...

It's possible but not easy...

Surface[x(S) u + (1 - u) x(D) + r (1 - u) (cos(a) cos(v) - sin(a) cos(b) sin(v)), y(S) u + (1 - u) y(D) + r (1 - u) (sin(a) cos(v) + cos(a) cos(b) sin(v)), z(S) u + (1 - u) z(D) + r (1 - u) sin(b) sin(v), u, 0, 1, v, 0, 2pi]

(I have a problem with angles 3D a or b...<180°...normal!)

...

https://ggbm.at/1389097 1

hello

I know how to do curves; my question is : if GG can do (-4.38998, 1.55355, 0) + (-0.77505 cos(t) - 1.78087 sin(t), 5.64937 cos(t) - 0.24432 sin(t), 3.02355 sin(t)) dynamically from A,B,C why I can not use the expression for next calculations?

saludos

PD: more (-4.42415, 1.02285, 1.5537) + (± 0.32628 cosh(t) - 2.35512 sinh(t), ± 0.64844 cosh(t) + 1.37528 sinh(t), ± 0.18058 cosh(t) - 0.68313 sinh(t))

see ±

the bold expression was copied and pasted from GG 1

Hi,

with mathmagic way...

saludos

https://ggbm.at/1389103 1

hello

great work with texts. I hope GG does this easier like in

thanks

saludos 1

Hi Jean 1

Hi

For polyhedra have the tool and command for construct a net, but how can construct

1. a net of cone?

2. a net of cylinder?

Thank´s 1

Hi,

1. a net of cone?

2. a net of cylinder?

another examples on GGT... 1

Thank you very much.