In this work, we extend the characteristic-featured shock wave indicator based on artificial neuron training to 3D high-speed flow simulation on unstructured mesh. The extension is achieved through dimension splitting. This leads to that the proposed indicator is capable of identifying regions of flow compression in any direction. With this capability, the indicator is further developed to combine with h-adaptivity of mesh refinement to improve resolution with less computational costs. The present indicator provided an attractive alternative for constructing high-resolution, high-efficiency shock-processing method to simulate high-speed inviscid flows.