Algebra and Trigonometry for Lighting Designers

[derekleffew]

So I've been thinking about my future book titled Algebra and Trigonometry for Lighting Designers. Filled with, you know, fun stuff like this:

Deriving a lighting fixture's multiplication factor from its beam angle using trigonometry:
[Excel format] Multiplying Factor(MF) =2*TAN((x/2)*PI()/180),
where x is the beam angle in degrees.

Note: the "*PI()/180" portion of the equation is just to force Excel to express the answer in degrees rather than radians, and therefore isn't needed if calculating by hand.


I've realized I need collaborators. Other than "W=VA" and "P=IE in your E=IR," what are some other formulas/calculations you use regularly? This may end up just being a pamphlet rather than a book, and will in inevitably become a wiki entry, so any/all help is appreciated.

[phil000]

Originally Posted by derekleffew

So I've been thinking about my future book titled Algebra and Trigonometry for Lighting Designers. Filled with, you know, fun stuff like this:
Deriving a lighting fixture's multiplication factor from its beam angle using trigonometry:
[Excel format] Multiplying Factor(MF) =2*TAN((x/2)*PI()/180),
where x is the beam angle in degrees.
Note: the "*PI()/180" portion of the equation is just to force Excel to express the answer in degrees rather than radians, and therefore isn't needed if calculating by hand.
I've realized I need collaborators. Other than "W=VA" and "P=IE in your E=IR," what are some other formulas/calculations you use regularly? This may end up just being a pamphlet rather than a book, and will in inevitably become a wiki entry, so any/all help is appreciated.

I made a smart excel.
http://www.divshare.com/download/2880495-a92

You'll notice it is all password protected...The password is controlbooth2007, I trust you guys to rearrange as you want it, as I'm going to put this in my portfolio for upcoming stuff, I'd appreciate it if you just left my name on it.
Enjoy. Distribute.
Hopefully this is a good first post.

[derekleffew]

Hey, Phil000, an excellent first post. Be sure to start a new thread in the New Member Board. Tell us all about yourself, we're kinda nosy. People will ask you all sorts of strange questions, just ignore them.

I like your spreadsheet, I have to investigate it some more. I never thought about using charts, that's cool. Here's the one I use.

[SerraAva]

Sometimes use the Pythagorean Theorem to find the throw distance of the light. Measure straight down from the light to stage level if its your target, then to where your focusing from that point. a^2 + b^2 = c^2 or (a^2 + b^2)^1/2 = c where a is your height, b is your length, and c is your throw distance. You can then multiply c by your MF to determine beam size.

[gafftaper]

Nice Spreadsheet Phil and welcome to the booth.

This is the modification I would like to see in a photometric spreadsheet. I want to be able to manually enter:
Instrument Height, Height above deck of target (for example 6' for head height), Horizontal distance to target, and the downward angle of the instrument. Both your sheet and Derek's automatically calculate Throw distance and beam angle. But I want to accurately know what's going on 6' above the deck. Simply changing the height in your sheets, changes the angle and results inaccurate information. So it would be great if all four of those factors were independent.

[phil000]

Originally Posted by gafftaper

Nice Spreadsheet Phil and welcome to the booth.
This is the modification I would like to see in a photometric spreadsheet. I want to be able to manually enter:
Instrument Height, Height above deck of target (for example 6' for head height), Horizontal distance to target, and the downward angle of the instrument. Both your sheet and Derek's automatically calculate Throw distance and beam angle. But I want to accurately know what's going on 6' above the deck. Simply changing the height in your sheets, changes the angle and results inaccurate information. So it would be great if all four of those factors were independent.

I can make them independent, should have it done by the end of the day...

the only problem is that the angle function in Excel in on some serious crack. It can prove consistency, but if you try and create a 30 60 90 triangle, it'll say like 54 degrees for the 60 degree angle...
Just for you buddy :
http://www.divshare.com/download/2880495-a92
Phil

[derekleffew]

Originally Posted by gafftaper

Nice Spreadsheet Phil and welcome to the booth.

This is the modification I would like to see in a photometric spreadsheet. I want to be able to manually enter:
Instrument Height, Height above deck of target (for example 6' for head height), Horizontal distance to target, and the downward angle of the instrument. Both your sheet and Derek's automatically calculate Throw distance and beam angle. But I want to accurately know what's going on 6' above the deck. Simply changing the height in your sheets, changes the angle and results inaccurate information. So it would be great if all four of those factors were independent.

You want to manually enter the downward angle of the instrument? You'd need a level and a protractor to physically measure that, and we're generally more concerned with the angle of elevation (at least McCandless was) so you'd need to take the complement, not that I'm complimenting you. Maybe Phil understands your desires better than I do.

Check out this for a real-time web-based tool. Does it do what you want?

[icewolf08]

Or, if you already own LightWright, you can use BeamWright, which does all the photometrics work for you, and will let you place an instrument anywhere relative to a subject. It also has a huge library of fixtures built in. John McKernon rocks!

[derekleffew]

Oh, Alex, you take all the fun out of it with your practicality. I recently bought LW4, after not having used it since the late '80s when it was ALDpro, and have yet to explore BeamWright. Totally agree that John McKernon rocks!, and he's a big Mac-Head too.

Anyone remember Great American Products' "Chart-A-Beam"? I could never afford it, and made do with homemade cardboard triangles, as I was a starving college student.

[phil000]

Originally Posted by derekleffew

Oh, Alex, you take all the fun out of it with your practicality. I recently bought LW4, after not having used it since the late '80s when it was ALDpro, and have yet to explore BeamWright. Totally agree that John McKernon rocks!, and he's a big Mac-Head too.
Anyone remember Great American Products' "Chart-A-Beam"? I could never afford it, and made do with homemade cardboard triangles, as I was a starving college student.

I really put the time into this sheet to have it be something sendable to everyone with a PC, and most likely excel. I've seen lightwright, and that's nice, but I like being able to see ALL of my instruments at once...

I developed this for my college. Since then, it's been used:
to grade all of lighting I's projects for 2 yrs now

Used to do most of the lights for Diviners
All of the lights for Urinetown
A good amount of the lights for Lysistrata, and keeps adding on more...


...And I'll add those other things gafftaper wanted...see first post...working on the angle idea (Some people are never satisfied...)

Phil