The “constant class” error message is interrogate’s way of telling you that this class is an abstract base class, annd you have to derive from it and implement the interface it required. Sadly, you can not do this in Python.
–> If you can use C++ then you can derive from BulletBaseCharacterController, and implement the interface. I have tried once, but without satisfying results.
–> If you want to use Python just implement your own class which is not derived from BulletBaseCharacterController. Use a ghost object or a kinematic rigid body, and control it yourself. You don’t need to add it to BulletWorld - this is just for automatically updating the character controller. Nothng you can not do yourself.
Either way is not not the faint of heart, and it might be very well that a few handy methods required for the Python way are not exposed yet (but this can be chaged).
I agree that the incomplete Bullet character controller is a huge drawback, and suggest using either Coppertops great work with ODE, or the PhysX character controller. For the Panda3D truck we will be waiting until Bullet has fixed this missing feature, or until we spot some open source game using Bullet which has implemented it’s own character controller for Bullet, and which doesn’t mind if we borrow some ideas.