Final answer:
When drawing a figure with an arm pointing directly toward the viewer, an artist would use the technique of foreshortening to create the appearance of depth and a three-dimensional effect in the two-dimensional space.
Step-by-step explanation:
If an artist were to draw a figure whose arm was pointing directly toward the viewer, the artist would need to use foreshortening. This technique is key in creating the illusion of depth and perspective in two-dimensional artwork. Foreshortening involves the artistic effect of shortening or compressing the lines of the object that is at an angle to the picture plane, giving the appearance that it extends into the space and recedes away from the viewer. The Renaissance movement was instrumental in developing the use of foreshortening, with artists like Michelangelo applying the technique to create depth and realism in their work. For instance, Michelangelo's David exemplifies the application of foreshortening to render the human form more dynamically. Notably, foreshortening exaggerates the part of the object closer to the viewer, which in this case, would be the subject's outstretched arm.