Model control method want!!

Hi, I want to control a 3D model with keyboard input, I think in the following way. Preparation: 1) 3 X files. One is the STILL model, one is the RUN model and one is FIRE model. Their model properties are remain unchange such as # of vertices, # of face and texture. The only change is vertices position. Flow: 1) Load all the X files into memory. The STILL model data will treated as reference model. 2) When I pressed a key "R", I will try to update the model to RUN model. The method is looping for all the vertices in the model and generate the intermediate position. So, I will hopefully "smooth" animation depend on the framerate I can have. 3) For the FIRE model is same as (2). I want to know is my thinking work and your helps are certainly welcomed. P.S. In fact, I will try to use the method in doing PS game too. Gavin