UAV simulation of obstacle avoidance in Gazebo?

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I would like to simulate some 3D path planning capabilities of an UAV in Gazebo. So Firstly, I download a point cloud of an outdoor area with obstacles. Can find any in internet.Than Load the point cloud to Gazebo. After that,convert point cloud to 3D model (something like this point clouds convert). So for this purpose I can use any type of UAV available in a standard ROS packages, or e.g. some of the MRS dronesDrones

So my question is how to show 3D path planning capabilities of an UAV: e.g. given a starting location, show how does the trajectory avoids obstacles in the 3D model?

Any help on that?