As suggested, I rewrite my code to make it simpler and directly showing the problem. Here is a short example. I'd like to generate 3D plot where x,y,z (= a,b,answer) while I am varying a (0
a = 0.2(*constants*);
b = 0.5(*constants*);
matrix = RandomReal[{-1, 1}, {4, 2}];
matrix1 = matrix[[All, 1]];
matrix2 = matrix[[All, 2]];
inter1 = a/b matrix1;
inter2 = 1/b matrix2;
inter = inter1 + inter2;
answer = Total[inter]