A new method for computer-generated holography is introduced, based on stacking zero crossings of partial wavefields and then quantizing. A fast method for finding the zero crossings when each partial wavefield results from a point source in space is discussed. Experimental results for three-dimensional object reconstruction are restricted to binary holograms, and they are obtained by a thresholding scheme. Normally, when zero crossings from different wavefields are superimposed, the hologram saturates after several hundred three-dimensional object points. In the new method this problem is removed by the thresholding scheme. Experimental results relating to three-dimensional objects with arbitrary object points in space indicate that the method has potential.