FC Around & Find Out
or......Angled Photometrics Jawn
Define the job by a known focal distance or by the coverage perimeter you actually need to light. Every photometric mode uses the same derived throw and aim.
Named scenarios
Browser-saved scenarios remain on this device. Download or share the calculation currently on screen as a portable .fcfo file; imported IES profiles are embedded.
No scenario selected.
Working calculation: Fixture Data and Job Geometry are shared across Area Math. Each calculation mode retains its own deployment inputs.
Fixture data
Define the photometric sources once, then select any ready source in Direct Focus, Linear Coverage, or Mirrored Coverage.
Known output
Use the published center-beam FC from a known throw. Beam angle is the full angle, not the half-angle.
FC
FT
DEG
Zoom calibration
Two published or measured center-beam readings. The throws may be different; the app normalizes them.
Point A narrower or wider is fine
DEG
FC
FT
Point C same fixture and output mode
DEG
FC
FT
DEG
Enter two calibration points to estimate output.
IES photometry
The file is read in this browser. Type C LM-63 files with TILT=NONE are supported in this version.
DEG
Optional IES zoom estimate choose matching color/output modes
DEG
DEG
DEG
Enter the measured zoom for Profile A and Profile C.
DEG
Choose one IES file—or several files for different zooms and color modes.
Recent Sources
Successful calculations appear here for quick recall. Uploaded IES files must be reloaded after the browser closes.
Direct focus
Analyze one fixture aimed at one focal point. Choose a horizontal target plane or the conventional plane perpendicular to the beam.
Complete a source in Fixture Data to make it available.
Calculates the beam intersection with a horizontal surface at focal-point height.
Linear Coverage
Choose which valid calculation supplies the footprint and intensity. The row is treated as repeating, so weaker end fixtures do not distort the average.
Complete a source in Fixture Data to make it available.
Horizontal mode supports direct-distance or Coverage Area geometry.
DEG
Measured from straight down.
Using the aim calculated by Job Geometry.
%
FIX
FT
Requested overlap is maintained; total coverage may expand beyond or fall short of the selected Job Geometry axis.
The heatmap and primary statistics use the complete finite row. An interior repeating-bay average remains available as a secondary comparison. Physical fixture spacing and focal-point spacing are equal because every fixture retains the same tilt and orientation.
Mirrored coverage
Two mirrored fixture rows aim inward across one shared horizontal coverage plane. Quantity per side is always editable; Auto-fit provides a geometric starting point.
Complete a source in Fixture Data to make it available.
DEG
Measured from straight down.
Uses the selected source’s current height and aim.
FIX
Uses nominal footprint coverage. Does not guarantee the FC target.
%
FT
%
Fixture rows run across the aiming direction, using oval width along each row and oval length between the opposing rows.
Job geometry
All heights use the same zero. Coverage Area derives the horizontal focus distance from the perimeter, fixture-row offset, and aim depth.
FT
FT
FT
FT
FT
Horizontal distance from the fixture row to the nearest edge of the area.
FT
FT
FT
FC
%
A blank or zero target leaves compliance inactive while photometric results remain live. The output factor applies to every source, including imported IES data.
New calculation · enter fixture height and job geometry.
Fixture Data
Define a reusable photometric source.
Enter known output, calibrate a zoom, or load IES photometry.
Inputs changed — recalculate to update results
Beam footprint at focal height
Top view of the exact cone intersection with the horizontal plane.
aimed focal point
oval center
Coverage target
—
Stage Area ≥ Target FC
—
Meeting-target area
—
Below-target area
—
Actual throw
—
diagonal distance
Physical Aim Angle
—
from straight down
Center illuminance at throw
—
plane perpendicular to beam
Illuminance on focal plane
—
includes cosine loss
Live fixture geometry · side elevation
Finite-row coverage layout
Nominal 50% footprints, overlap, and dimensioned coverage for the entered fixture quantity.
Oval length
—
Oval width
—
Near edge from plumb
—
Far edge from plumb
—
Pinned comparison
A = pinned · B = latest valid resultPin a valid result to compare it with the next calculation in this mode.
Calculation Assumptions
What the two illuminance numbers mean: published center-beam output is normally measured on a surface perpendicular to the beam. “Illuminance on focal plane” applies the incidence-angle cosine for the horizontal plane you entered. This is clean geometric photometry—not an IES calculation—and does not model field angle, beam-edge falloff, lens distortion, shutters, or atmospheric loss.