////////////////////////////////////////////////////////////////////////
//Question 1: how to draw lines for Z axes out to matrix data?
//Question 2: how to draw spline3d on the surface of drawned graph?
//Question 3: - hardest how to draw multidimensional trend of that graph?
// For all the answers - congratulations (I spend 20 hours on that) :-)
// My email tkostanjevec@gmail.com - From Slovenia

function [xx,yy,zz]=graf3d(A)
[n,m]=size(A) // matrix A


X=zeros(4,(n-1)*m)

    for i=1:(n-1)
      for j=1:(m-1) //posebej za j=m
        X(1,(i-1)*m+j)= A(i,j)*cos((j-1)*2*%pi/m)
        X(2,(i-1)*m+j)= A(i,j+1)*cos(j*2*%pi/m)
        X(3,(i-1)*m+j)= A(i+1,j)*cos((j-1)*2*%pi/m)
        X(4,(i-1)*m+j)= A(i+1,j+1)*cos(j*2*%pi/m)
      end
    end
 
    for i=1:(n-1)
        X(1,i*m)= A(i,m)*cos((m-1)*2*%pi/m)
        X(2,i*m)= A(i,1)*cos(0)
        X(3,i*m)= A(i+1,m)*cos((m-1)*2*%pi/m)
        X(4,i*m)= A(i+1,1)*cos(0)   
    end  
 
Y=zeros(4,(n-1)*m)

    for i=1:(n-1)
        for j=1:(m-1) // posebej za j=m
          Y(1,(i-1)*m+j)= A(i,j)*sin((j-1)*2*%pi/m)
          Y(2,(i-1)*m+j)= A(i,j+1)*sin(j*2*%pi/m)
          Y(3,(i-1)*m+j)= A(i+1,j)*sin((j-1)*2*%pi/m)
          Y(4,(i-1)*m+j)= A(i+1,j+1)*sin(j*2*%pi/m)
        end
    end
 
    for i=1:(n-1)
      Y(1,i*m)= A(i,m)*sin((m-1)*2*%pi/m)
      Y(2,i*m)= A(i,1)*sin(0)
      Y(3,i*m)= A(i+1,m)*sin((m-1)*2*%pi/m)
      Y(4,i*m)= A(i+1,1)*sin(0)   
    end  


Z=zeros(4,(n-1)*m)

  for i=1:(n-1)
    for j=1:m
      Z(1,(i-1)*m+j)= i
      Z(2,(i-1)*m+j)= i
      Z(3,(i-1)*m+j)= i+1
      Z(4,(i-1)*m+j)= i+1
    end
  end

xx=X
yy=Y
zz=Z

f=plot3d(xx,yy,zz) 

endfunction

A=[30	10	5	5	20	10	10	10
30	11	6	7	17	8	6	15
31	12	6	6	15	8	7	15
33	12	6	7	15	8	8	11
34	14	7	8	13	9	9	6
32	15	6	7	14	7	8	11
34	16	4	6	12	8	9	11
36	18	4	4	11	7	10	10
37	19	3	3	11	7	7	13
38	19	2	3	10	8	6	14
43	17	2	2	12	8	8	8]
xtitle("3D") 

graf3d(A)