vivianiscurvetnb.jl

begin
    using Plots

    r = 10
    x(t) = r*(1+cos(t))
    y(t) = r*sin(t)
    z(t) = 2*r*sin(0.5*t)
    R(t) = [x(t), y(t), z(t)]
    t_range = range(-2π, 2π, length=100)

    tnb_anim = @animate for t_at in t_range
        plot3d(x.(t_range), y.(t_range), z.(t_range), legend=false, aspect_ratio=:equal,
        xlims=(-5,25),
        ylims=(-11,11),
        zlims=(-21,21),
        camera=(30, 15),
        color=RGBA(241/255,90/255,34/255,0.5),
        linewidth=5,
        )

        plot3d!([R(t_at)[1]], [R(t_at)[2]], [R(t_at)[3]], color=:black, marker=:circle, markersize=3, label="t = $t_at")

        # T
        T_hat = R'(t_at)/norm(R'(t_at))
        arrow!(R(t_at), 2.5*T_hat, color=:red, label="T", linewidth=3, aspect_ratio=:equal)

        # N
        N_hat = cross(R'(t_at), cross(R''(t_at), R'(t_at)))/(norm(R'(t_at))*norm(cross(R''(t_at), R'(t_at))))
        arrow!(R(t_at), 2.5*N_hat, color=:green, label="N", linewidth=3, aspect_ratio=:equal)

        # B
        B_hat = cross(T_hat,N_hat)
        arrow!(R(t_at), 2.5*B_hat, color=:blue, label="B", linewidth=3, aspect_ratio=:equal)
    end
    gif(tnb_anim, "tnb.gif", fps=20)
end