I have a known radius I’m supposed to match yet retain the same reveal all long it’s length. The curved movie screen is yet to be installed or I woudl pull measuremenst from it.
Any idea how I can determine where my points will be every 2′ along the length of the radius.
This is for a ceiling in a theater 26′ A.F.F. The theater si not big enough to pull a line on the floor.
ML
Replies
I failed high school trig but I still know the answer. Play it safe. Wait until the screen is installed.
If you go ahead, using any mathematical equation, and your method doesn't fit the screen, you're ski-rude. You can talk about your brilliant math solution, until your blue, but you'll still be doing the job over.
True. Only problem is I have to get the man lift out of there before the screen is installed. and get the radius cut in and tile dropped.ML
Joe Fusco has a solution on his website at http://www.josephfusco.org called "laying out really BIG arcs"
In that case, I'd want the screen's maker to provide all the relevant dimensions, equations and practical solutions. Got to make them take some responsibility too.
Edited 8/21/2008 8:04 pm by Hudson Valley Carpenter
ditto
Lay it out on ACAD and scribe the arc using the full radius. ACAD doesn't care if the center of that arc is 200+ feet outside the room.
Then place your reference points on the arc and draw a line from each point on the arc to an arbitrary point inside the room. Pick a point that you will be able to measure to/from with a tape measure, say, the centerline of the back wall or something.
Finally, draw chords from each reference point on the arc to the next one; (you need points at each end of the arc, too).
Now get the precise length of each of those false radii and chords off the drawing with the 'dimlin' command. Then go lay it out in the real room using those measurements.
That ought to work. But if it were me, I'd call up the screen manufacturer and demand that he send me a full-size cardboard template.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
That 238'3" radius will give you 13 3/4" of total rise if the run is 45'. I used my Construction Master pro with OC spacing set for 2' and this is what it returned:
At the center 13 3/4
then working each direction at 2' increments-
13 11/16
12 3/8
11 7/8
11 3/16
10 1/4
9 1/8
7 13/16
6 5/16
4 5/8
2 11/16
0 0 5/16
So you could mark this layout on the floor and connect the dots to get your radius. The arc length itself is 45' 13/16".
It's an accurate way to do it. With that large of a radius there's not much to the curve between each 2' section. I don't know the exact dimensions to the theater, I just guessed at the 45' measurement, but it's really simple to figure with a CM pro.
Edited 8/21/2008 10:20 pm ET by kpatrix
Thanks Since we have 14 of these to do I'll be picking up a CM today.ML
Here's a direct link to the article that Mathewson talked about:http://www.josephfusco.org/Articles/Big_Arcs/big_arcs.html
Can you believe Monica is now 28 years old?
Seems like just yesterday she was crawling around the White House on her hands and knees.
Thanks Since we have 14 of these to do I'll be picking up a CM today.
So if the screen doesn't fit, you'll point a the CM software box and say, "He did it! Make him fix it."
IMO, you should speak with the GC and insist that the screen maker provide you with their method of creating the radius. It's really a simple matter of working cooperatively with them to achieve the desire result.
If you go your own way and the two don't match, you'll be stuck in a finger pointing contest which the screen maker will likely win. Why? Because they'll say, "We've been doing this for years and we've never had this problem before".
You won't have a leg to stand on, because this is your first attempt to create an arch under these conditions.
Because the equation involved is not easily understood and cannot be visualized by the average person, you'll have no practical way to demonstrate why your method is the correct one.
Edit: I was once assigned the job of building a bulkhead form for an arched doorway in a two feet thick concrete wall on a new building at West Point. Of course I asked the foreman for the radius of the arch, saying, "Not the diameter, the radius".
He went into the trailer and got someone to give him in the radius off the print. He came back and told me that it was eighteen feet.
That seemed too large for a people doorway so I asked him to go back and get it in writing, from the super.
He returned with a note, initialed by the super. It read, "radius, nine feet".
Edited 8/22/2008 4:08 pm by Hudson Valley Carpenter
HVC.... I do agree, that why they are having us hold 5' from the CMU They have given us the radius we are just to match that with the apex being 60" from the CMU. We are still a few feet back from where the screen is to be installed. Originally they wanted a curved soffit going from ceiling line up to the deck. 26' feet in the air go one is going to even see the soffit ML
OK. Best wishes. Let us know how it comes out. Photos would be interesting.
I can do that. This is gonna be one high end theater.http://www.muvico.com/press_releases.aspML
Ah, you'll be working in 1000 Hoax eh? I did a small remodel job in a condo out there, a few years ago. Nice area.
Nice area, but 85 miles from home. Not enjoying that.ML
Make sure you get the Construction Master Pro V.3+. As long as you are dealing with a true radius as opposed to something elliptical you should have no problems. The keystrokes are fairly simple, you can either use a known run and rise, or a known run and radius, or a known rise and radius. The only thing that is "confusing" is the run is the overall span as opposed to the run of a roof being half span. If you have any questions just holler, I'll be glad to help.John