[buco]

If I've understand the problem the solution is simple: it's not a problem :p . I mean: the way the surface is deformed is due only to proc textures you use in the displacement shader. These textures are random and infinite so the effect you mentioned is the result of a fractal calculation and if it gives you the illusion of a wave hitting a box (on that particular frame) it's just a coincidence. Obviously the more the mesh is subdivided the more detailed will be the deformation so try to open the the property panel for your mesh and play with the subd level display number (as you go on with the tut remember to put it back to the values Philip suggested). Then if you want to play with the waves' height open the surface editor and change the y scale for the texture.