Shading and rendering in the URDF tutorial

I have followed the URDF tutorial and made my own robot: http://gazebosim.org/tutorials/?tut=ros_urdf I have not changed the rrbot.world file with it's sun lighting and I use gazebo materials, Gazebo/Orange. The problem is that the shading is very strange, for example the wheels change between orange and black when they rotate, it's like the light source is rotating with the wheels. For the meshes I have tried STL and Collada exported from onshape. This is the robot rendered in gazebo:  This is the robot rendered in rviz:  I have tried many different ways of tags inside the tags:Gazebo/DarkGrey Why are the visuals in Gazebo rendered so porly? I'm not sure where to start looking for a solution. [C:\fakepath\goal.sdf](/upfiles/15487810494508323.sdf)