This was just me getting my center of inertia at origo while the model had its origo at a random position (not center off mass or a corner).Gazebo/SDF wants the models to have its model origo at the center of mass.
I am not looking for a "perfect solution" i am only looking for an easy/fast way to test different mechanical links in gazebo.
I would like to design a passive dynamic walker and experiment with different mechanical linkage to generate different gaits
I have looked at the blender plugin and it looks very potent, but that is not what i need.