  This paper presents a generalized framework for the simulation of multiple
robots and drones in highly realistic models of natural environments. The
proposed simulation architecture uses the Unreal Engine4 for generating both
optical and depth sensor outputs from any position and orientation within the
environment and provides several key domain specific simulation capabilities.
Various components and functionalities of the system have been discussed in
detail. The simulation engine also allows users to test and validate a wide
range of computer vision algorithms involving different drone configurations
under many types of environmental effects such as wind gusts. The paper
demonstrates the effectiveness of the system by giving experimental results for
a test scenario where one drone tracks the simulated motion of another in a
complex natural environment.
