3D animation

   With 3D animation models are created and rigged for a animator to animate.

   To start with a model is made and built up from scratch with polygons in a 3D modeling program for example maya. The model if to say it was a human like character it would have individual parts for limbs that need to be rigged and also anything else that needs to produce movement. These parts are rigged with joints and a skeleton so the model can contain any sort of motion that can be made.
Once done the animator then focuses on making the model move as realistically as possible/or to just have a very smooth animation.

   3D animation you cant just start where you like because you must literally bring your character to life first before you can actually accomplish your goal.