I'm curious about how to calculate the boundary normal in DualSPHysics. In my opinion, the boundary normal generally calculated by the particle and its neighbour particle(last or next one). Therefore, the boundary particle ID is generally successive which means one by one in the pre-process. But after I pre-process the initial particle distribution with the Generate.exe, the boundary particle ID is not successive. So, I'm curious about how to solve the normal of the particle. Is there an additional code for searching neighbour particles of the boundary particle after the pre-process?
Thank you very much!