Lower lip: the lower lip changes gently, and the left and right lip nodules form two microprotrusions. The lower lip can be divided into three sides horizontally and vertically. Don't copy the tone and ignore the expression.

Corner of the mouth: a very important part where the mouth connects with the face. Pay attention to the light-dark relationship formed by the intersection of the corners of the mouth through the edges of the lips, which is a very important detail in the expression of the mouth.

Because of the different angles of painting, the perspective of the mouth should be based on people, and the proportional relationship between the left and right size of the mouth and the upper lip nodule should be drawn according to the perspective law of near-large and far-small. This gap should not be drawn too wide, but must be expressed by comparing the overall width ratio of lips.

Secondly, when drawing lips, don't blindly emphasize the inherent color of rosy lips. Usually, the upper lip is slightly heavier than the lower lip. When representing the lip edge, don't hook the lip edge contour, that is, don't draw the edge like a silhouette, but show more volume.

Matters needing attention

When expressing the object's mouth expression, we should pay attention to the changes of mouth crack caused by the opening and closing of upper and lower lips, as well as expressions such as smile and pain. When performing, you can first master the fluctuation and depth change of the mouth shape standard, and then deal with it flexibly according to the actual situation of the model. Don't simply draw the mouth crack into a straight line.