An ongoing research topic is to build suitable visualization architectures for anthropomorphic conversational user interfaces which will run on different devices like laptops, PDAs and smart phones. One interesting way to handle the performance restrictions on small and mobile devices are scalable avatars and animations. An idea to speed up our animation system based on morph targets is presented, to achieve this the number of animation weights for the morph targets is reduced dynamically. This method is optimized by regarding the graphical structure and dependancies of the morph targets.