# Help needed on flats



## AyCee (Jun 9, 2006)

I'm sort of new to scenery design, so I hope someone will be able to help me with such issues!  

I've attached a 3D rendering of a scene from my production, and in this scene, I've designed 6 - 8 flats (on wheels) to be set around the stage. These flats are about 10m tall and 1.5m wide. Is this dimension absurb? I've got a friend who told me that it's not feasible as the flat will sure topple regardless of the weight of the base. I'm not sure how true it is, so need some advice from you people!


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## drawstuf99 (Jun 9, 2006)

Just by thinking on this and without any _physical_ support, I think that deminsion is a bit "out there."

Either the base or brace of the flats would need to be quite big (extend out behind the flat) or it will just fall over.

It looks like a good idea, but I don't know if it would be possible seeing that it is on wheels. If these were anchored into the stage with bracing and didn't move, then this is perfectly OK to do; however, you would still need a longer brace.

Do I make sense? hehe.

Also, by looking at your rendering, it looks like a good deal of the height of the flats will be out of light for the most part, and I'd start and think if this will be the case in your venue. If so, then if you can't see a large chunk of the flat, would it really be neccesary to have it there? Though, maybe it is part of the look you want - I like how tall it is because of the more space it gives the scene.

Anyway, stuff to think on.


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## jbeutt (Jun 9, 2006)

So these only need wheels so they can be moved around the stage or are they just being flipped around?

The amount and style of bracing depends entirely on the materials. What are you making these out of? If you can get them light enough, then you could reduce the needed diagonal bracing in back. However, no matter how light it is, you'll need a certain amount of floor bracing (flat on the ground and connected perpendicularly to the bottom of the flat. and of course you'd need the flats to be reinforced to keep from wobbling around and the joint at the bottom would have to be very strong.
This is doable, but not with wood. You'll need to make a metal flat and skin it with muslin or lauan. That may even be too top heavy and require some thinking as to how to get it lighter.
The easiest thing, I think, is make these flats static. Then you can build all the upstage bracing you want because no one will be able to see. It's when they move apart from each other and around the stage that that sort of bracing will get noticed. Of course, if you make them static, then you might as well fly them to save yourself the space the bracing would take up.
In either case, metal framing is the way to go.


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## soundlight (Jun 9, 2006)

I have never heard of a ten _meter_ tall flat. I think that that's a little tall, and would be out of the light. Why do the flats have to be ten meters tall?


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## jwl868 (Jun 9, 2006)

Absurd, I suppose is in the eye of the beholder. [Although they may be right in this case.] So I tried to figure out an objective analysis of the problem.

At 10 m (meters, right), that is a lot of leverage to contend with if the flat starts to tip forward. You say it is on wheels, so I assume that its on some kind of trolley/carriage, and for the sake of the discussion, I’ll assume that the trolley is 1.5 meter wide by 3 meter deep (but of course it could be deeper than that) (I’ll be honest at this point, I am having trouble with how stable this structure may be). But forging on, I’m assuming that the problem is a balance of torques: one for the tipping vertical flat and the other for the trolley and counterweight.

For the vertical flat, I am assuming that weight of the vertical flat is “concentrated” at the midpoint vertical distance (5 m). For the trolley, I am assuming that weights must be placed about three quarters of the way from the flat, 0.75 x 3 m = 2.25 m. 

The real question in this problem is how far forward will you let it tip before it falls over? (My gut feeling is that the answer could be “not at all”, but I don’t know if any flats are held to that standard.) But, for the sake of discussion, assume that the flat can tip forward 10 degrees (that’s about 2 m forward at the top.). Any assumption of acceptable tipping assumes that the flat will not get pushed accidentally and will be carefully maneuvered. Deciding the “acceptable tipping angle” will require serious thought. For example if a “normal” 2.5 m to 4 m high flat were to fall forward, it stays on the stage and only the actors are in the way. But a 10 m flat may reach the audience. (Not to trivialize the actors’ safety, but they may see it coming and get out of the way, or turn/react to protect themselves, etc.)

Okay, back on track: 

Torque (T) = F x L x cosine a

Where F is the weight in kg (I’m fudging units here a little, I usually use US lb, but the force conversion units will cancel down in the calculation anyway)
L is the distance from the pivot point to the weight
a is the angle between horizontal and the arm L

If the flat has tipped forward 10 degrees, the angle a for the flat is 80. Meanwhile, the trolley has lifted up 10 degrees and angle a for the trolley is 10 degrees.

So the equation to balance:

T of flat = T of trolley

Now, assume that the front flat weighs 82 kg (about 180 lb – I’ve assumed using 2x4s, something substantial to support 10 m), then you have:

82 kg x 5m x cos 80 = Weight on trolley x 2.25m x cos 10

82 x 5 x 0.17 = Weight x 2.25 x 0.98

Weight = 32 kg (70 lb)! With the weight of the flat (82 kg), that’s a lot of weight to be wheeling around.


I suspect that I’m being conservative here (for example, I have ignored the weight of the trolley and weight of any back bracing and I’ve made some conservative assumptions on the design materials and weight). (On the other hand, if a more conservative tipping angle of 15 degrees is used, the weight is 50 kg. [110 lb]) [When I apply the same math to a more typically sized flat (2.5 m to 4 m high), I get a reasonable counterweight value (3 to 5 kg).] 



Although not related to the original question, erecting the flat from horizontal to vertical may be a structural problem in and of itself, depending on the materials of construction and design. That is, 10 m (30 feet) of a span supported at only one end; it could buckle under its own weight as it is being pushed up. 

Further, if the flat isn’t that rigid, the flat might wobble back and forth if it is moved quickly or hit by something – if that wobble moves beyond the angle of the design tipping point, it will fall over.

Also, this will have to moved smoothly. A sudden start or sudden stop will get it tipping forward.



Any chance you can fly this in as fabric drops?


Joe


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## cutlunch (Jun 9, 2006)

From looking at your plan I was wondering why these need to be flats. Is there a fly floor in your venue. Unless there is a practical reason for them to be flats I would make them material banners. They can be wieghted at the bottom to make them stiff. If they are there permanently then they can even be fastened to the floor.


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## AyCee (Jun 9, 2006)

Wow... so many replies!  Ok to clear some airs..

Actually I do think that 10m tall sounds a bit too weird. I chose this height because the proscenium opening is 9.8m, and since these flats are used to represent walls and pillars of houses, I thought it might be better if it is as tall as the proscenium opening. I could be wrong in this aspect, though, as I've never deal with flats of this nature.

I've thought of flying them too, but because these flats are arranged in different positions on different scenes, so if I were to fly them, I'll need to make many more sets. If not, I'll have to redesign the positions of these flats to make it easier to fly.


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## drawstuf99 (Jun 9, 2006)

I think you'll find that your set wont neccesarily need to be as tall as the prec arch because when your lights or focus all eyes will go to your set and not the curtains and backstage. Nobody will notice really, but I love the depth and scale you get when you use that tall of flats correctly (as in your design).

I like the idea someone mentioned about the banners, but I also understand not wanting to build more... hmmm.

I wonder if you could maybe create some sort of really tall box (CLOSE to the deminsions you say - not that close, but close enough to be supported) and then be able to turn them around for diff scenes. Does that make sense? You'd still have to watch the top weight though. Let me think on that or ask a builder friend of mine.


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## AyCee (Jun 10, 2006)

Do you mean have the flats just as tall as where the "edge" of the lights? So basically if I just light up the lower half of the stage, I can just make these flats at just slightly over 5m? That sounds good to me!  


drawstuf99 said:


> I think you'll find that your set wont neccesarily need to be as tall as the prec arch because when your lights or focus all eyes will go to your set and not the curtains and backstage. Nobody will notice really, but I love the depth and scale you get when you use that tall of flats correctly (as in your design).


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## cutlunch (Jun 10, 2006)

Now I have more info I agree with using the 5 Metre Flats. As has already been mentioned you don't need to light to the top at 10 metres. It is a matter of perspective. When compared with the height of the opera singers the flats will still tower over them. Also depending on how many positions there I would not light the whole back of the stage ie the curtain and the flats. If you just light the flats it will help give some depth to the stage. But it depends on how far forward the flats will be and if any action happens between them.


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## jonhirsh (Jun 10, 2006)

drop your theatres teasers in and cut off more of the opening if there at the back of the stage just do some sightine on your paperwork and youll realize that really from 5 rows back in a raked theatre you cant really see much of the back side of the stage. 

Just cut down the size or fly em. 

But just to give you an idea i worked on a tv show and we had wild walls these are flats on wheels the flat was about 15' high so about 4.5 meters and it had almost an 300 pound weight on it to stop it from keeling over. but it was made of plywood and all sorts of crazy stuff

[IMGL]http://i7.photobucket.com/albums/y265/phunkinrad/doodlebops.jpg[/IMGL]


thats a pic of the set. 

So its possible but those were a ***** to move it took 3 people to do it .
JH


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## DarSax (Jun 10, 2006)

jonhirsh said:


> [IMGL]http://i7.photobucket.com/albums/y265/phunkinrad/doodlebops.jpg[/IMGL]



Sorry to go off topic, but when I opened this thread and I saw this picture, I just kind of stopped and was like :shock:


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## jonhirsh (Jun 10, 2006)

lol its a werid pic. 

JH


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## kingfisher1 (Jun 12, 2006)

have you tryed foam insulation? being much much lighter then ply wood it might work in your torque formula...


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## AyCee (Jun 13, 2006)

I've not tried on that, but will it be very flimsy?

Actually I have no idea about this technique, as I only know how to design, but not really well-versed in the technical aspects of stage design. Also, this production is supposed to be staged overseas, so most likely we'll not be making the scenes on our side, but get some people to make at the other side.


kingfisher1 said:


> have you tryed foam insulation? being much much lighter then ply wood it might work in your torque formula...


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## AyCee (Jun 13, 2006)

I second to that!  
Don't supposed it's a kids' show? You'd scare the kids! Haha!

jonhirsh said:


> lol its a werid pic.
> 
> JH


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## jonhirsh (Jun 13, 2006)

Well it is a kids show and they love it werid? Its the number one preschool kids show in america right now... 


JH


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## jwl868 (Jun 15, 2006)

A height of 5 meters (about 15 feet) is much more manageable than 10 m. The frame can be built with 1x3s or 1x4s at that size. (Are 16-foot 1x4s available?) You’ll still have to design the bracing and carriage, but that knocks about three quarters of the weight off the scenario I assumed in my earlier post. The facing of the flat will add weight that will need to be considered.

AyCee: In your June 13 post, you note that these will be built elsewhere. That will require additional considerations. You will need to have either (1) prepare detailed drawings and specifications so that they can be built exactly how you want them, or (2) a large enough budget so that someone can design and execute the flats according to the general specifications that you want – height, width, facing material, image, mobility.

You may also have to consider transport of these flats from venue to venue. Should the flat/carriage be designed for disassembly and re-assembly? If not, is there room in the truck for the all of the assembled flat/carriages?

Another consideration may even be the other venues that you plan to use. Will your 5 m flats clear the lighting and teasers?

Joe


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## gafftaper (Jun 16, 2006)

That's just way too tall. Either go with the 4-5 meter flats or hang them. Assuming you have a full fly space, you could use flats suspsended from multiple battons to create depth and movement. Flying in and out differnet layers could be really interesting looking. 

A simple rule for building a jack to brace a flat. The horizontal support should be 1/4 the length of the height and the diagonal brace should reach 3/4 up the flat. So you would need a flat with a brace that sticks out 2.5 meters behind it. And yes the flat should be in the center of the rolling platform so that means your platform should be 5 meters long. If you built a fabric flat you could keep the weight down enough to minimize the counterweight but it's going to flop like crazy. 

Hang em!


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