Plot a 3D contour

I know it is applicable to plot a 2D contour for a function with 3 variables. For example, use contour(x,y,z) to plot a function z=ax+by.

Now here is my question. I have a function f=ax+by+cz, where a,b,c are constant, x,y,z are variables. I have to plot a 3D contour, for example, the contour for f=0.

Thanks in advance.

Answer 1

[Walter Roberson]

contour_at = 0;
isosurface(x, y, z, f, contour_at)

[Xu]

Thanks!