I see several examples (such as test_friction.world ) that specify mu/mu2/slip1/slip2 in the link/collision/surface/friction/ode namespace.
I also see some examples (such as this one ) that specify mu1/mu2/slip1/slip2 in the <gazebo> namespace.
Aside from the mu vs mu1 question, which one is correct? Or are they two ways of the same thing?