Systems and methods for generating and concatenating 3D character animations are described including systems in which recommendations are made by the animation system concerning motions that smoothly transition when concatenated. One embodiment includes a server system connected to a communication network and configured to communicate with a user device that is also connected to the communication network. In addition, the server system is configured to generate a user interface that is accessible via the communication network, the server system is configured to receive high level descriptions of desired sequences of motion via the user interface, the server system is configured to generate synthetic motion data based on the high level descriptions and to concatenate the synthetic motion data, the server system is configured to stream the concatenated synthetic motion data to a rendering engine on the user device, and the user device is configured to render a 3D character animated using the streamed synthetic motion data.