They are serval tools for creating illusions of three dimensional space and they includes:
Overlapping: Overlapping in art is the placement of objects over one another in order to create the illusion of depth. Overlapping is when shapes are in front of other shapes. If one shape overlaps another it communicates an illusion of depth.
Changing Size and Placement: Changing size and placement is another method artists use to create a sense of depth in a painting. This technique states that larger objects appear closer and smaller objects appear further away.
Linear Perspective: Linear perspective, a system of creating an illusion of depth on a flat surface. All parallel lines (orthogonal) in a painting or drawing using this system converge in a single vanishing point on the composition’s horizon line.
How does linear perspective give the illusion of depth? Linear perspective is a drawing technique that gives the illusion of depth. In other words, it tricks the eye into believing that the picture in front of it is actually 3D, not 2D. Objects that are farther away from us appear smaller, so we draw them smaller to create that illusion of space and distance
Relative Hue and Value: Hue refers to the name of the color. A hue is a given color created by a specific wavelength of light. Value is the degree of light and dark of a color. You can use it to create contrast and to add visual drama to your work. In watercolor, we add water (not white paint) to a mix to make it lighter.
Examples of hue and value in color includes: Green, orange, yellow, and blue, each of these is a hue, a color or a shade that’s true. A rainbow shows the melting of one hue into another, from red to violet, and all shades in between. The noun hue means both a color and a shade of a color. Green is a hue, and turquoise is a hue of both green and blue.
Atmospheric Perspective: Aerial perspective, also called atmospheric perspective, method of creating the illusion of depth, or recession, in a painting or drawing by modulating color to simulate changes effected by the atmosphere on the colors of things seen at a distance.