In Creo Illustrate, you can create animations by manipulating the components of your assembly. To shrink the springs from a length of 70 mm to 50 mm, you would need to create keyframe animations by adjusting the dimensions of the springs over time. You can use the Animation workspace in Creo Illustrate to set up the animation timeline and define the desired changes in dimensions. Further details on how to create animations in Creo Illustrate can be found in the software's documentation or online tutorials.