## field

## field

### field(id)

Builds an empty field **id**..

**Options:**

**CG(id2)**: central field **poi(CG matrix vol(id2)**, if id2==0
**poi(CG matrix vol(vol vertex(v))** for any vertex **v** of volume **id**.

**coe(c,v)**: forces are multiplied by **c** (1 default), their viscosity is **v** (0 defaut).

**dim(3)**: 3D field (default), **dim(2)**: 2D field.

force(x,y,z,v): uniform field.

**poi(x,y,z)coe(c,v)**: central field.

**poi(x1,y1,z1,x2,y2,z2)**: cylindric field with axis **(p1,p2)**.

**poi(x1,y1,z1,x2,y2,z2,x3,y3,z3)**: planar field with axis **(p1,p)**. and p in plan **(p1,p2,p3)**.

**law(v)**: field inversely proportional to the distance power **v**.

**law(x1,y1,z1,x2,y2,z2, ...)**: the force field is function of the distance according to
law **w**.

**limit(x1,y1,x2,y2)**: significant window (defaut -DX/2,-DY2,DX/2,DY2).

**secz(3)**: 3D (default), **secz(2)**: 2D.

**Note:** to enable the fields do yes field.
## central field

If the field has a single point **P** lines of force are spheres of center**P**.

With option **radius(r)** the field is the sphere center
the point and radius **r**.
## field func

### fiel(id)func("f")

Builds the field **id** runing the anyflo function **f(p)** returning the force applied
at point **p**.
### fiel(id)func(num)

Builds the field **id** runing the C function **field_utilisateur(field, num, poi, force)**
returning the force applied at point **p** with **field** -> object field **id**.

**Options:**

**coe(c)**: coeficient.

**poi(x,y,z)**: position.
## field image

### field image(id1)

Returns the identifier of the field assocoated to image **id1**.
### field image(id1)=id2

Changes this identifier.

**Note:** the image **id1** will be activated by only the field **id2**.
### fiel(id1)image(id2)

Builds the field **id1** associated to the image **id2**.

**Note:**

The value of the field **id1** at point **(x,y,z)** is **2*k-1** where
**k** is the color of the pixel **(xi,yi)** of the image **id2**
### fiel(id1)image(id2)axix(x,y,z)

Builds the field **id1**, whose forces are tangent to cylinder axis **(x,y,z)** on image **id2**.
### fiel(id1)image(id2)dila(x,y,z)

Builds the cylindrical field **id1**, axis **(x,y,z)** on image **id2**.
### fiel(id1)image(id2)dilx

Builds the cylindrical field **id1** axis **(1,0,0)** on image **id2**.
### fiel(id1)image(id2)dily

Builds the cylindrical field **id1** axis **(0,1,0)** on image **id2**.
### fiel(id1)image(id2)dilz

Builds the cylindrical field **id1** axis **(0,0,1)** on image **id2**.
### fiel(id1)image(id2)rotx

Builds the field **id1**, whose forces are tangent to cylinder axis **(1,0,0)** on image **id2**.
### fiel(id1)image(id2)roty

Builds the field **id1**, whose forces are tangent to cylinder axis **(0,1,0)** on image **id2**.
### fiel(id1)image(id2)rotz

Builds the field **id1**, whose forces are tangent to cylinder axis **(0,0,1)** on image **id2**.

**Note:**

The value of the field **id1** at point **P** is **f=t*(2*L-1)/d** where:

**t** = normal to plan **(P,axis)**.

**L** = luminance of the pixel

**d** = distance(P,axis).

if dim(image) < dim(window): interpolation between the pixels of the image.

do generate image field(id1) whenever the
image is modified.
## field rota

If the field has two points **P1** and **P2** lines of forces are circles axis P1->P2.
## field rotx

If the field has one point **P** lines of force are circles Px axis.
## field roty

If the field has one point **P** lines of force are circles Py axis.
## field rotz

If the field has one point **P** lines of force are circles Pz axis.

# EN DEVELOPPEMENT

### field(id)image vertex(s)vol(id)

Returns
### field image vertex(s)vol(id)

Returns the parameters of the field of image type associated to vertex **s** of volume **id**.
### field image vertex(s) vol(id)=num,kr,kv,kb,dx,dy,dz

Changes these parameters.

**Notes:**

1) In dynamic animation, if the volume **id** (or vertices **s**)
is provided with a mass, each of the vertices **s** undergo a force field
direction (dx, dy, dz) and amplitude (kr * r, k * v, kb * b), with (r,v,b) = pixel color of
image **num**.

2) Volume **id** must be isomorphic to a grid(grid, ball, rev, geod, filet, ...).

3) **field image vertex(n1)vol(n2)=n3,kr,kv,kb,"n"**
defines the direction as the normal at vertex **s** of volume **id**.
### field image vol(id)

Returns the parameters of the field of type image associated at volume **id**.
### field image(id)=num,kr,kv,kb,dx,dy,dz

Changes these parameters.

**Notes:**

1) In dynamic animation, if the volume **id** (or vertices **s**)
is provided with a mass, each of the vertices **s** undergo a force field
direction (dx, dy, dz) and amplitude (kr * r, k * v, kb * b), with (r,v,b) = pixel color of
image **num**.

2) Volume **id** must be isomorphic to a grid(grid, ball, rev, geod, filet, ...).

3) field image vol(n1)=n2,kr,kv,kb,"n"
defines the direction as the normal at each vertex of volume **id**.
## field vertex

### field vertex(s)vol(id)

Returns the numbered fields associated at vertex **s** of volume **id**.
### field vertex(n1)vol(n2)=c1,c2,...

Changes these numbers.
## field vol

### field vol(id)

Returns the number of fields influencing the volume **id**.
### field vol(id)=n1,n2,...

Change these numbers.

**Note:** in dynamic animation, volume **id** will undergo fields numbered volume **n1,n2,...**

### field(idf)vol(idv)

Builds the field **idf** whose the centers are the vertices of volume **idv**.

**Options:**

**near**: the force applied at point **p** is these of the nearest vertex of the
associated volume **idv**.
## field vol vertex

### field(id)vol(id2)vertex

Builds field **id** type **vol vertex**.

All vertices of volume **id2** will be considered as
central fields with properties of field **id**.

Useful for create a forces field the shape of a volume acting
on a particles system.

# DEVELOPING

### field vol vol(id)

Returns the parametres of ´field vol´ property of volume id.
### field vol vol(id)=v1,f1,d1,v2,f2,d2,...

Changes these parameters.

**Notes:**

1) In dynamic animation, the vertices of volume **id** will be repelled by those of volumes **vi**
by a force **f** between 0 and **fi** when the distance varies between **di** and 0.

2) Avoids collisions between the volume **id** and the volumes **vi**.

3) Vertices **s** must have masses.

4) **fi**is the order of 1 to 100, **di** is the order of 1.0 to 2.0

fi est de l´order de 1 a 100, di est de l´ordre de 1.0 a 2.0.

the more volume 1 is "thin" , more di bigger must be vi

the more **vi** is "fast", more **fi** bigger must be.
## See also: