Synopsis
		sfpwave3d > Fdat.rsf verb=n nt= ot= dt= nx= ox= dx= ny= oy= dy= nz= oz= dz= vel=1.0 cx=1.0 cy=1.0 cz=1.0

generate a plane in t-x-y-z space
cx x + cy y + cz z - vel t = 0
(the plane goes through the origin)

Parameters
		float cx=1.0   float cy=1.0   float cz=1.0   float dt=   float dx=   float dy=   float dz=   int nt=   int nx=   int ny=   int nz=   float ot=   float ox=   float oy=   float oz=   float vel=1.0   bool verb=n [y/n] verbosity flag