A mixing -multiplication- of a sphere and of a 'thick' helix defined by means of three bidimensional fields [Un mélange -multiplication- d'une sphère et d'une hélice 'épaissie' défini à l'aide de trois champs bidimensionnels].
A mixing -multiplication- of a sphere and of a 'thick' helix defined by means of three bidimensional fields [Un mélange -multiplication- d'une sphère et d'une hélice 'épaissie' défini à l'aide de trois champs bidimensionnels].
X = Fx(u,v)
Y = Fy(u,v)
Z = Fz(u,v)with:
u ∈ [Umin,Umax]
v ∈ [Vmin,Vmax][Umin,Umax]*[Vmin,Vmax] then defined a bidimensional rectangular domain D.
v ^
|
V |...... ---------------------------
max | |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
| |+++++++++++++++++++++++++++|
V |...... ---------------------------
min | : :
| : :
O------------------------------------------------->
U U u
min max
X = Mx(i,j)
Y = My(i,j)
Z = Mz(i,j)with:
i = f(u,Umin,Umax,Nu)
j = g(v,Vmin,Vmax,Nv)where 'f' and 'g' denote two obvious linear functions...
x 
= 
Fx
x 
= 
Fy
x 
= 
Fz