Calculations

Months – This field allows the user to specify which months of the year to use for the design daylighting calculations. This field must include the solstices: December (12) for winter solstice and June (6) for the summer solstice and it must only contain months between December and June (ie. 12, 1, 2, 3, 4, 5, 6). If design results for a fall month are desired, choose the corresponding spring month. The months should be entered without quotes and separated by a comma.

Design Start Time – This field indicates the first time that will be calculated for each day selected. The time must be an integer and input in 24 hour clock form. This start time is only used in the design calculations, the annual calculations will be performed for hours between sunrise and sunset.

Design Stop Time – This field is the last time that will be calculated for each day selected. The time must be an integer and input in 24 hour clock form. This stop time is only used in the design calculations, the annual calculations will be performed for hours between sunrise and sunset.

Design Time Step – This field is the time step between calculation times for the design calculations only. The times calculated will always include noon, 12:00PM, and will vary off noon by this time step. The start and stop times will always be calculated.

Analysis Time Step – This field is the time step between calculation times for the analysis calculation matrix. The times calculated will always include noon, 12:00PM, and will vary off noon by this time step. The start and stop times are sunrise and sunset times for the analysis calculation matrix. Note that every time specified on the “Site and Usage Input” sheet are still calculated for the annual simulations, interpolated as necessary from the analysis calculation matrix.

Create Renderings – This field requires either Yes (Y) or No (N) and tells SPOT whether or not to perform renderings of the space. If this option is selected the renderings will begin simulating upon getting to the Photosensor Generator page and they will be viewable while on the Calculating page. The rendering can be viewed on the Calculating page even if not selected to pre-calculate on the Advanced Options page however the user will have to wait at that time for the renderings to finish.

Field Point Spacing – This field allows the user to specify the spacing distance to use for the calculation grids. If left empty, the program will auto-size the calculation grid to fit the defined geometry width and length. Typically auto-sizing will result in a grid with between 10 and 15 rows and columns. WARNING – A small grid size for a large space will result in a large calculation grid and long calculation times. See the Photosensor Generator section for grid size limitations.

Field Wall Spacing – This field defines the offset the calculation grid will have from the walls of the space. The default offset is 2 feet or 0.5 meters.

Equinox 9am and 3pm? – This field forces SPOT to calculate the Equinox at 9am and 3pm times, regardless of the other time step, start and stop time settings. These times are commonly needed for LEED and other daylight metrics.