Inserting a Photometric Grid

 

To insert a photometric grid:

1.	Ensure that each lighting instrument contributing to the illumination is focused.

The light beams do not have to be drawn for calculations to be made.

2.	Click the PhotoGrid tool from the Spotlight tool set.

3.	Click on the plot to insert the photometric grid. The grid is a rectangular object, and can be inserted in Center-line Placement mode or Edge Placement mode.

 

Placement Mode	Description
Center-line	Click once, and then again, to define the width through the center of the grid. Click again to specify the width of half the grid.
Edge	Click once, and then again, to define the length along the edge of the grid. Click again to specify the grid width.

The photometric grid calculates and displays the illumination values at its elevation point. The values are displayed in either foot candles (Imperial) or lux (Metric), depending on the units selected in File > Document Settings > Units. If Use Threshold Settings is selected, colors indicate the illumination range according to the Threshold values set in the Object Info palette.

 

Color	Description
Gray	Illumination value of zero
Green	Illumination value between zero and Lower Threshold
Tan	Illumination value between Lower and Upper Threshold
Blue	Illumination value above Upper Threshold

The photometric grid range colors can be changed. See Customizing Photometric Threshold Colors.

4.	To evaluate the illumination values at different heights, change the elevation of the photometric grid in the Object Info palette.