HELP - Complex Geometric and Angular Shapes

Hi! I am an Architecture student currently learning how to confidently use sketchup. I am looking for a way in which to create complex angular shapes similar to: Rough rock/cliff faces and Daniel Libeskinds architectural work. If anybody has any tips or methods on how to quickly achieve this type of shape it would be greatly appreciated. Thanks

With the help of Line, Move, Rotate tools and YouTube search