How to draw a cube, cast it’s shadow, and shade it.

Draw a Horizon line near the top of the page.

Draw a basic cube using two point perspective. Mark two vanishing points at both ends of the horizon line. Below and between them, draw a straight vertical line representing the front edge of the cube. Draw orthogonals from the bottom of the edge to each vanishing points. Repeat for the top of the edge. Draw vertical lines to represent the two side edges of the cube. Draw orthogonals from the top of those edges to the opposite vanishing points. The top corner of the cube's back edge will be at the point those two top lines intersect.

Erase the major construction lines. Now you're going to draw the "invisible" edges, or the edges that aren't visible from your perspective. Draw a light line from the bottom right corner to the left vanishing point. Repeat for the bottom left corner. Draw in the back edge.

Erase all the construction lines. Now you have a transparent cube.

Now you're going to choose the general direction of your shadow. Pick a point on the ground to the left of the cube. Lightly draw three lines, connecting the point with the three corners of the base, closest to that point.

Draw three parallel lines that represent the rays of the sun. Each sun ray should pass through the top corners of the same three edges connected to the ground rays. Draw lightly, so you can erase later.

Now you can define the shape of the shadow. Mark a point where the ground ray and the sun ray which pass through the back edge intersect. Mark the same intersection points for the rays on the side edge, and the front edge.

Draw the outline of the shadow by connecting the dots to the front and back edges. Erase all the sun rays and ground rays.

Paint in the background of the page with a light grey-brown. Leave the cube white.

Paint in the area of the shadow that will be visible with a dark gray value. Erase all the "invisible" lines.

Paint in the two sides of the cube. Choose a middle gray (a value halfway between the dark gray shadow and white). Paint the side of the cube in shadow with this middle gray. For the left visible side of the cube, choose a value very light gray (just a little darker than white).

Paint sky in above the horizon. To create the illusion that the ground recedes into the distance, blend red into the ground toward the bottom of the page and blue for further away.

Gently erase the harsh outlines. This creates the illusion of realism, as we don't see outlines in real life. The meeting of planes, usually represented by an outline, is simply a change in value. Accentuate the form by applying the following rule: where two planes meet, gradually darken the darker one, and lighten the lighter one.