How to approach the following implicit equation using MATLAB?

I have a scalar nonlinear equation f(x,y,z)=0 where x=x(u,v), y=y(u,v) and z=z(u,v). Using the equation, I want to create a plot of u and v. How to approach? Directly substituting u and v in place of x, y and z is not working, because the function f then becomes a large expression, mostly consisting of user defined functions.

[John Chilleri]

Look into the fplot3 and fimplicit3 commands - they might help!