What is typically used to ensure actors are at varying heights for visual appeal on stage?

Using rostra is a common technique in theater production to create varying heights among actors on stage, enhancing visual interest and depth in the performance. Rostra are platforms or raised surfaces that can be strategically placed to elevate certain performers, allowing for a more dynamic staging. This variation helps draw the audience's eyes and can symbolize different character statuses or emotional states, adding layers to the narrative being presented.

When actors are positioned on rostra, it can also affect how they relate to one another spatially, making interactions more visually engaging. This method is often employed to create a more balanced and aesthetically pleasing composition for the audience.

Other techniques, such as set dressing, typically focus more on the decoration and atmosphere of the set rather than actor positions. Key and set props serve different functions related to lighting and physical objects used by performers during a scene, respectively, rather than affecting the height dynamics among actors on the stage.