How can I plot a 3D function?

I want to plot a function of two variables, but it's not explicit the terms of the function, for example: I have two vectors: mu_a = (a+v*t ; b+v*t ; c) and mu_b = (d+k1*t ; e+k2*t ; f), and I want to plot the function f(v,t) = K*exp(-0.5*(mu_a-mu_b)^T*SIGMA*(mu_a-mu_b)), where SIGMA is a matrix 3x3.

I do not want to manage algebraically the term into the exponential to explicitly find the function g(v,t) inside the exponential, I want to write the function in terms of the vector as it's written above.

Thanks in advance.