BeamWright Worksheet

BeamWright is a small, easy to use beam spread utility that will help the lighting designer choose the correct instrument. In addition to providing the designer with photometric information (beam spread and intensity), the program will also recommend a specific light. The program takes into account how closely the beam size matches the lighting area as well as the intensity of the light. It will choose from one or more types (Ellipsoidals, Fresnels, PARs...) and if the choice is a "zoom" unit (such as a Fresnel), the program will zoom to the correct beam size. A demo is available.

Example Problem 1:
How large a pool of light will be produced by an Altman 6x12 ellipsoidal hung at the center of the JFAC MainStage Cove and focused on an actor standing at the curtain line?

• First: Determine the height of the Cove above the stage floor (24 feet) and the
  Plan (horizontal) distance from the Curtain Line to the Light (26 feet).

• Open BeamWright
• Load the stgcrft.bw1 data file.
• Click the Show All button.
• Check Ellipsoidal under Instrument Types:
  
• Choose the instrument (Altman 6x12 Ellipsoidal) from the drop-down list box under Name:
  
• Enter the Trim Height and Floor Distance in the text boxes in the Criteria: section.
  
• Click the Draw as Entered button .
  or
  
• Use the scroll bars in the Section view to change the Trim Height and Floor Distance of the lamp
  
• Read the pool diameter, intensity, throw distance from the Results: section.
  

Screen Shot of BeamWright

• Answer: Size of the pool of light (field diameter) = 14.6 feet (14'-7")
  
• What will be the intensity? 152 foot candles
  
• What is the actual throw distance? 31.62 feet
  
• How many of these units will be needed to provide a 40' wide wash from this position? 4
  (Width_of_Wash / Wash_Spacing = Number of units)

Example Problem 2:
Which Altman Fresnel, 6" or 8", would you use to provide an 8' pool of down light from an electric pipe 24' above the deck?

• Open BeamWright
• Load the stgcrft.bw1 data file.
• Check Fresnel under Instrument Types:
  
• Enter the Trim Height (24') and Floor Distance (0') in the text boxes in the Criteria: section.
  
• Click the Draw as Entered button .
  
• Click the Find Best Match button .
  
• Read the instrument recommendation from the drop-down list box in the Name: section.
• Click the Find Others Like This button to develop a drop-down list of other instruments that might be acceptable.

Answer: 8" Fresnel at 3/4 spot focus.

Using BeamWright, which is loaded on the GateWay computer in the Theatre Classroom (JC129), solve the following problems.

1. How large a pool of light will be produced by an ETC Source 4 19° ellipsoidal hung at the center of the JFAC MainStage Cove and focused on an actor standing at the curtain line?

2. How many Altman 6x9s will it take to provide a 40' wide front wash at the curtain line from lamps mounted in the Cove?

3. Which Altman Fresnel, 6" or 8", would you use to provide a 12' pool of down light from an electric pipe 18' above the deck?

4. Which Altman ellipsoidal would you use to light an 8' lighting area at the curtain line from the far cove of the Capitol Theatre? (Trim height of cove = 24' -- Plan distance from far cove to curtain line = 27')

5. Which ETC Source 4 ellipsoidal would you use to light a 12' lighting area at the curtain line from the near cove of the Capitol Theatre? What alternative units (both ETC and Altman) are available? (Trim height of cove = 24' -- Plan distance from near cove to curtain line = 12')