You can do raytracing in DM's, which allows you to graph the type of equations.
Read a tutorial or book on raytracing, that should theach you the basics.
If the equation has an analytic solution it's not that hard (check out my Lift-Off pack for some examples of raytraced sphere's and cylinders. Feel free to use anything, just give credit
where credit is due.) For the cooler surfaces, you'll need an approximate solver, take a look at UnConed's presets like VJ Chmutov for and example.