Volume rendering is one important method for 3D data visualization. Volume data for volume rendering often includes a lot of empty voxels

resulting in decreasing the rendering efficiency for ray-casting algorithms

because meaningless resampling positions may be computed. This paper presents a GPU-based volume rendering method for full-empty sub-data blocks to efficiently improve the rendering speed. The sub-data blocks with a lot of empty space are effectively managed with an octree structure. By rendering surfaces of the non-full-empty sub-data blocks of leaf nodes in the octree

the start and end resampling positions of the ray-casting algorithm are closer to the visible part in the data volume. Meanwhile

the appropriate leaping steps are calculated to quickly skip the full-empty sub-data blocks according to the lookup result of the full-empty subdata blocks confirming texture. As a result

the meaningless resampling points are greatly reduced and the new algorithm

which is based on the selection of the depth of octree and effectively ski-pping full-empty subdata blocks

shows better performance than the original GPU ray-casting algorithm with bounding box surface rendering when the data volume contains a lot of empty voxel. The new improved algorithm is successfully applied in seismic data visualization

with an opacity function designed to highlight the layer surfaces in the data volume

which shows favorable practical effect.