Footprints™ Frequently Asked Questions
-
Why do I get a "Settings File Missing" error when I try to launch Footprints?
-
Why are your HID photometric files rated at 1000 lumens? What should I do to correct this?
-
How do I center the printed output on an 8.5 x 11 inch page?
-
Why don't the gridlines in the background show up when I print?
-
Why do you only allow 3 isolines for the default "Factors of 2" isoline preference?
-
Isn't it possible to create a template that can be used for any mounting height?
-
Why do other template generators produce different templates for the same input data?
-
Why is Footprints Installer trying to load when I launch Footprints?
Q: Why do I get a "Settings File Missing" error when I try to launch Footprints?
A: The "settings.dat" file must reside either in the same folder as "footprints.exe" or in a folder specified via a command line parameter.
See below for a discussion of the latter approach.
Q: Can I share Footprints over a network with my co-workers?
A: Yes, we recommend doing this and assigning one user the task of updating the shared executable as newer versions become available; users will have the ability to customize their own "settings.dat" file. Follow this procedure:
1) Have each user install the software on their PC.
2) Have one user copy "Footprints.exe" and "settings.dat" onto the network.
3) Have each user REMOVE Footprints from their PC using "FootprintsInstaller.msi".
4) Have each user create a new shortcut on their Desktop for the shared executable on the network.
5) Have each user copy the shared settings file to their PC.
6) Have each user modify the shortcut properties such that the Target reads exe-network-path dat-PC-path. For example:
W:\apps\Footprints\Footprints.exe C:\Program Files\Footprints\settings.dat
If users are on terminals (no PCs - just networked monitors with all processing and storage on one shared server) the system administrator should be able to store the DAT files under each User Profile.
Q: Why are your HID photometric files rated at 1000 lumens? What should I do to correct this?
A: This is called "prorating", and is actually a fairly common practice among luminaire manufacturers. There are really two reasons we prorate. First, luminaire manufacturers generally avoid showing a preference for particular lamp manufacturers, and using a generic (and arbitrary) value like "1000" is one means of preserving anonymity. Second, the value that pops-up in the "Lumens" input field of your lighting software should not (whether prorated or not) be simply accepted as-is, but rather changed to the lumen rating for the lamp you intend to use as published by the lamp manufacturer. These ratings are readily available online and in catalogs. Never use a text editor to modify the data contained in the IES-format photometric file itself.
Q: Where the heck did I just send my printed template?
A: Your default printer. We have assumed that the vast majority of users have set their default printer to a black-and-white, 8.5" by 11" paper machine. If you'd like to designate another printer as your default Footprints™ printer, follow this procedure:
1) On the task bar choose Start-Settings-Printers, right-click on the desired printer, and select "Set as Default Printer".
2) Launch Footprints™ (you must close and re-launch if already open), go to Tools-Settings-Printing and set the new printer as default, and File-Save to retain this change.
3) Go back to Start-Settings-Printers (on the task bar) and undo your default printer change. Now Footprints™ will have its own default printer!
Q: How do I center the printed output on an 8.5 x 11 inch page?
A: From the "Template Specification" screen go to Tools-Settings and adjust the Shift values under "Printing" to best suit your printer.
Q: Why don't the gridlines in the background show up when I print?
A: Is your "Show When Printing" box checked? If so, please contact us and we will attempt to resolve the problem.
If it isn't checked, check it.
Q: I want to use a 350W metal halide lamp, but you've only got IES files for 250 and 400W. What should I do?
A: Use the 400W test for the same optical system and change the lumens to 350W as described in a preceding Q&A. It would not be reasonable to expect a luminaire manufacturer to pay for tests of every available lamp. We would have to test for every lamp manufacturer (at least 4) and every model (standard, super, pulse-start, ceramic, etc.) offered for that wattage, yielding something like 16 tests. Further, lamps are continually being modified, so you'd have to retest after every change and for every new model. And that's for just one housing-distribution-lamp combination... It is generally more conservative to use a higher-wattage test. (Better 400W than 250W in this case.) Since HID optics are generally designed around a point source, performance generally worsens with increased arc tube size - it's better to err on the safe side. Make sure that everything else remains constant: reflector, lens, etc. A larger housing will often have its own (larger) reflector for a given distribution, and increased wattage can require the use of a sag lens. NEVER use a coated-lamp test to model clear-lamp performance, or vice-versa; similarly, it's generally NOT a good idea to use HPS to represent MH (dissimilar arc-tube geometry), or vice-versa.
Q: Why do you only allow 3 isolines for the default "Factors of 2" isoline preference?
A: This is done to encourage proper template usage. Only two lines are generally needed, one at the target minimum and another at half this value. A third line at one-fourth the target minimum can be useful in a rectilinear four-pole layout, but otherwise only contributes visual clutter. The "Specified" option allows as many as 7 isolines at whatever values the user desires.
Q: Isn't it possible to create a template that can be used for any mounting height?
A: Yes, if you show a background grid in units of mounting height and give a table showing isoline values for various mounting heights. For example, say you've created a template for 30' to lens, with curves shown for 0.25, 0.5, and 1.0 fc and labeled A, B, and C, respectively. One row in the table would show these original fc values and mounting height, and additional rows would show higher values for lower heights and lower values for greater heights. These additional fc values are found by multiplying the original fc value by the square of the ratio of original height to the new height. Refer to the Gullwing Applications Guide for an example of proper implementation of this approach. That said, there are two reasons not to do this. First, if you have software that can generate templates as you need them, why store any? Second, such a "universal" template is extremely limited in it's utility: You're stuck with the isolines you chose the first time around. In the above example, if you want to design to 1.0 fc minimum with a 35' height, you'll have to guess the size and shape of the 1.0 fc curve based on the curve now valued at 0.73 fc.
Q: Why don't you report the average?
A: To calculate the average you must determine the boundaries of the area of interest. A calculation of the average for the area covered by the square grid or the area "covered" by the template would be meaningless. Further, an average calculation usually considers contribution from neighboring luminaires; this is beyond the scope of a template generator.
Q: Why do other template generators produce different templates for the same input data?
A: There are several possible explanations for discrepancies between template generators, the two most likely being grid resolution and interpolation method. Our calculation grid spacing is simply one-tenth the optical height. This provides a high degree of resolution, while keeping the maximum calculated value independent of drawing scale. Other template generators sacrifice accuracy to reduce calculation time (via grid size) for low optical height / large scale combinations.
An explanation of our interpolation algorithm would be very lengthy, but you can check its relative accuracy with an exercise like the following: In Footprints™ print this IES file with 40000 lumens, 0.8 LLF, 32' height, 1.5' arm, no tilt, 30' scale, and 3 isolines for a 1.0 fc minimum. Repeat this with another template generator. Finally, do the same in AGI32® (or similar point-by-point software), but then create a calculation grid with twice our resolution (spacing = 1/20th the height = 1.6') and show isolines for the grid rather than simply creating a template for the luminaire. We believe you'll agree that Footprints™ outperforms other template generators.
Q: When I insert my DXF into a site plan DWG, the template is clearly out of proportion:
Either much too large or far too small.
What's going on?
A: There are two possible explanations. The first involves units. DXF output from Footprints™ is in "Decimal" (feet) units; if your site plan is in "Architectural" (inches) units, simply "scale" the template by a factor of 12. Otherwise, the drawing entities in the site plan DWG have been scaled in a clumsy attempt to plot to scale. The "dist" command in AutoCAD should ALWAYS reveal accurate dimensions for entities in model space, but some users will, due to inadequate understanding of the software, actually shrink their (electronic) drawing entities by a factor of 1/20 to get their plotter to draw at 1"=20' scale! So to make your templates work on such a distorted site plan, you can either follow suit or correct their DWG. If you scale your template, make sure the background grid still makes sense...
Q: Why is Footprints Installer trying to load when I launch Footprints™?
A: Have you recently relocated "Footprints.exe" to another folder? This is the most likely cause. The best way to resolve this is to simply remove and reinstall the software.
Feel free to contact our Applications Engineers (800) 227-0758 if you need further assistance.
