This post is taken directly from my book Entertainment Design; Scenic, Lighting, and Sound, with Vectorworks...
Sidebar: Creating the End Seat Symbol
The End Set symbol is a hybrid symbol that uses only 2D objects.
Create a new document, and assign Design Layer 1 a scale of 1/2"=1' 0" (1:25). Then go to the Top/Plan view and select the Circle tool. Place an 18" (457.2 mm) diameter circle at 0-0. By default, this circle should be filled with white and have a black stroke. Duplicate the circle in place, or draw another circle and fill with black.
Use the Clip tool in the Removes Inside mode and Clipping by Rectangle mode and snap to the center 0,0 point. Click drag to remove the lower right quadrant of the circle.
Repeat to remove the upper left quadrant.
Double-click the Line tool to insert a 24" (609.6 mm) horizontal line centered at 0,0
and repeat to create a vertical line.
Select All and assign a medium line weight.
With everything still selected, go to Modify>Create Symbol and create the symbol End Set Plan View. Make sure that Plan Projection Center is selected as the Insertion Point and click OK.
Right-click on the symbol in the Resource Browser and select Duplicate. Name the new symbol "End Seat." Now, right-click on the End Seat symbol in the Resource Browser, and select Edit. Then click the 3D Component button in the next dialog.
In the Front view and drawing in the Symbol Definition plane, draw another set of circles, fill, and clip as in the plan. This time, place the center of the circle at +3' 9" (1143 mm) up on the Y axis. The 3' 9" (1143 mm) height is the typical height of a person's eyes when sitting in a chair. Draw a 24" (609.6 mm) horizontal line through the center of the circle and draw a vertical line from 0 to 5' 0" (1524 mm) through the circle.
Go to the Top view and Select All. Select the Rotate tool in the Rotate and Duplicate mode. Rotate and Duplicate the object 90°, and you will end up with this in the Right Isometric view.
Exit the symbol, and save.
Consider creating and assigning a class or two to the symbol/symbol components.