Scilab Function
Last update : September 1994

eval3dp - compute facets of a 3D parametric surface

### Calling Sequence

  `[Xf,Yf,Zf]=eval3dp(fun,p1,p2)`

### Parameters

- `Xf,Yf,Zf`: matrices of size (4,n-1*m-1). `Xf(:,i)` ,`Yf(:,i)` and `Zf(:,i)` are respectively the x-axis, y-axis and z-axis coordinates of the 4 points of the ith four sided facet.
- `fun`: a Scilab function.
- `p1`: a vector of size `n`.
- `p2`: a vector of size `m`.

### Description

`eval3dp` computes a four sided facets representation of a 3D parametric surface defined by the function `fun`. `fun(p1,p2)` computes the x-axis ,y-axis and z-axis coordinates of the corresponding points on the surface, as [x(i),y(i),z(i)]=fun(p1(i),p2(i)). This is used for efficiency.

### Examples

    p1=linspace(0,2*%pi,10);
    p2=linspace(0,2*%pi,10);
    deff("[x,y,z]=scp(p1,p2)",["x=p1.*sin(p1).*cos(p2)";..
                                "y=p1.*cos(p1).*cos(p2)";..
                                "z=p1.*sin(p2)"])
    [Xf,Yf,Zf]=eval3dp(scp,p1,p2);
    plot3d(Xf,Yf,Zf)

### See Also

`genfac3d`, `plot3d`,