We present a novel surface reconstruction algorithm which can directly reconstruct surfaces with different levels of smoothness in one framework from height fields using 3D discrete grid ray tracing. Our algorithm exploits the 2.5D nature of the elevation data and the regularity of the rectangular grid from which the height field surface is sampled. Based on this reconstruction method, we also develop a hybrid rendering method which has the features of both rasterization and ray tracing. This hybrid method is designed to take advantage of GPUs newly available flexibility and processing power.