Lighting Symbols

Hi Clay,

The footprints shown by some manufacturer-provided light fixtures in Land F/X are not an appropriate tool for designing for footcandle requirements -- rather they're a visual aid for the beamspread of the light fixture. (Specifically, the border of the footprint or cone represents the angle at which the light intensity is 50% of maximum).

A footcandle/lux focused tool is probably one of the most requested items on the wishlist of lighting design features. Unfortunately I don't have an ETA on that, but it won't be in 2025. With that said, if you have any examples, resources, or suggestions you could share about how you'd like to see such a tool work, that would be greatly appreciated and help the development process.

In the meantime, I'll make a note on the wishlist item that you expressed interest.

Alex

HI Alex,
Thanks for the answer. I guess seeing a layer labeled LUX made me think it could be used to determine FC.

I guess I don't understand what you mean by "light intensity is 50% of maximum"?

As for the footcandle/lux tool . . . I imagine something like your irrigation uniformity tool. Maybe there is a user option to set the baseline fc. Where the plan shows area that are less than, equal to, or greater than the defined fc. Another way could be <1fc ,1-5fc, 5-10fc, etc.

I made that a bit unclear. Here's a better explanation:



A light's footprint in Land F/X is an isoline of constant footcandle/lux, drawn based on two things:

• the light's beam angle (i.e. the wider the beam angle, the larger the footprint)
  
• the height of the light fixture (i.e. the higher the light fixture, the larger the footprint)
  

Note that the light intensity (lumens) is not a factor. Consequently, if two light fixtures share the same beam angle and the same height, they'll have the same footprint, even if one is a 100 lumen lamp and the other is a 10,000 lumen lamp.

You're absolutely correct that the "LK-LITE-LUX-###" layer name describes the illuminance in lux at the footprint isoline, as a result of the intensity of that particular light.

These footprint isolines can be used, for example, to aid in determining the spacing between identical path lights (i.e. how the light cones overlap), but because non-identical light fixtures have footprint isolines at different lux values, they should not be interpreted as if they all represent the same value like the contour lines of a topographic map.



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Thanks for the suggestions on fc/lux tool functionality. That sounds pretty in line with what we've heard from others as well, so I'd say we're getting an increasingly clearer picture of what to build.