Sightlines, in a theatrical context, refer to the lines of sight available to spectators of a performance. For the set designer, this concept can be used to ensure that the key elements of a production can be viewed by the spectator.
Why Sightlines are Important
When creating a floor plan and working from the perspective of looking down at your design from above, it can be easy to miss how certain areas of the stage may be obscured from view when the viewer looks from another viewpoint. Walls, furniture, columns, platforms, or other elements might block views of the stage for spectators in certain seats in the theater.
Testing Sightlines
As you get more experienced in design work, you will probably develop a sense for how tall pieces will obscure large areas of the stage in front of them (particularly if those pieces are located near the front of the stage), or how certain pieces upstage may actually overlap if they are separate pieces, or if there are performers on top of platforms. To test these ideas, it may be helpful to build a cardboard scale model of your design and view from different viewpoints at eye level. Take your sketch at first glance and view your design from that viewpoint as well.
Beginner Tip: When creating a scale model, consider placing human scale figures at all entrances and acting areas and on top of any platforms. You can test your design more thoroughly by placing a human scale figure in your primary acting areas. Take pictures of these areas to see if the human figures can be seen from each viewpoint.
If you are finding that it is difficult to see the figures from certain views in your model, you may need to move or lower certain pieces or create larger openings. You could also consider if your acting areas can be moved.
How Open Should the Design Be?
You do not need to create a design that can be seen in its entirety from every viewpoint and your design does not need to offer the same view from each seat in the theater. This will likely sacrifice any sense of space, height, depth, or level changes. However, it is helpful to make sure that your key areas are visible from as many viewpoints as possible. A certain amount of obscured areas is OK if you would like to hide certain elements for dramatic effect (perhaps it is an important moment in the show).
A more limited view (available only from center seats) will sacrifice the importance of the viewing experience for those seated to the sides, though, and the viewer may not understand the importance of this area. To explore more about this idea, consider different viewpoints. How well can you see the set pieces when looking down the aisles?