1 Introduction Facial expressions are one of the most important parts of animating a 3D character, we are sure that every work done to get the Character animation is important, all the parts together make a good character animation, however, facial expressions reflect a person's emotions. Just by looking at his face, or even just his eyes, you might know how he feels. Body movements can help emphasize the action, but they may not be necessary to understand it. This was not an easy task, due to the complexity that the characters have when interacting with others. Nowadays, computer-generated characters are very common, they are not only present in animated films; They also appear in other sections in video game form, so it is crucial to make each part as detailed as possible, as viewers may notice a slight change in the character's face. Facial expression has always been studied by animators, so that they can improve it later. and the two fields that always participate in it are physiology and phycology. But depending on the type of animation we are making, the expressions will be different, some will be more realistic and others will be more exaggerated. In this thesis, we will review the different types of animation and how they use facial expression. We will review cartoonish and realistic character animation, as well as common techniques used in order to obtain the expected result.2 Facial Animation TechniquesFirst, to obtain a good facial expression, one must model the face of the character, and there are two ways to do this, those based on geometric manipulations and those based on image manipulations. Each style has its...... middle of paper ...... parameterization is a way of parameterization which will allow you to obtain a more complex expression by articulating the muscles. There are different muscles that need to be taken into account when shaping a face. There are the lower facial muscles and the upper facial muscles. As Waters says in his research and this still today by many animators, he divides the face into 5 groups in the lower face which are: the upper and the lower, those which contract horizontally, the oblique muscles, the orbital and sheet muscles. And those that can change the appearance of the expression are located in the upper face and are the eyebrows, the forehead and the upper and lower eyelids of the eyes. There are three methods to achieve good muscle shaping: spring mesh muscle, vector muscle and layered spring mesh muscle.2.3.1 Spring mesh muscle2.3.2 Vector muscle2.3.3 Layered spring mesh muscle