Some questions about mesh in Toast

[Dustin Qi]

Now I'm modelling the complete problem of photoacoustic tomography, which means that I need to use TOAST to simulate the light propagation, and then use k-wave toolbox(another matlab toolbox) to model sound propagation. That is, the output from TOAST should be the input of k-wave toolbox. 
But k-Wave and TOAST use different numerical techniques (regular mesh in k-Wave and irregular mesh in TOAST), I don't know how to solve the problem. One way maybe interpolate the function from the nodes of the TOAST basis onto the points in the k-Wave basis in Matlab. But I don't know how to achieve it and  whether it's reliable and accurate. Is there anybody here and help me? Are there some information, papers or examples about it? Any answer would be helpful.
  Thanks.