Inertia

Inertia is the resistance of any physical object to any change in its velocity. An important element in simulation, inertia allows the physics simulator to calculate the correct dynamics of an object.

From left to right: cube, solid sphere, hollow sphere, solid cylinder, hollow cylinder. All shapes have the same mass and friction. The friction causes the cube to stay in place while the cylinders roll down the ramp as expected.

Here, both Ignition and Gazebo work as expected.