Sketch has no three-dimensional sense? Is it because? Isn't it obvious that the three shades of black, white and gray are distinguished? That is to say? Should it be black? Heavy? You are neither black nor heavy. You didn't light up where it should be? Some places should not be dyed. Don't be afraid? Where it is dark, it is darker, especially when the angle between the projection and the object is strangled. Pay attention to the connection between too many colored faces (gray faces) and black and white.

Color painting has no three-dimensional effect because your whole picture is gray? Or is the color of your too uniform? There is no solid color (you always have a variety of colors to blend pigments, and some parts, such as apples, can be used directly without color matching? For example, deep red) and pay attention to the use of complementary colors. There are one or two things in every painting that need solid colors? So that the picture can be bright? . Besides, what about the shadow part of the object? Dark green and red are unevenly mixed to draw? . . . Before painting, add black and green to the shaped object with a pencil? Or a black and red circle? Draw with a black border when painting? Do you also press the edge when painting the background color? So that objects will be more natural? I don't want to go around like a circle when I'm done. be .................