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Montell Taraschewski

Movable 4kw HMI on Dolly - Ideas required!

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Hello there everyone,

for an upcoming project we are required to move a 4kw HMI on some sort of dolly approximately 10-12m to simulate the sun moving across the room.
The caveat is, that our location is on the first floor. Which means I need some sort of a smart solution to secure a wind-up stand (extended all the way to approx. 4m)
against tipping over, whilst at the same time begin able to move it along the tracks. 

Ive been thinking about constructing a larger platform for a GFM Quad-Dolly made out of wood or similar material with extendable aluminum struts so we could tie the lamp
down to the platform in order to prevent it from moving. Not too sure if this will work though.

Maybe one of has had a similar issue in the past and would like to share her/his approche.

Thanks in advance and stay healthy,

Montell   

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If you need a really wide base, maybe two parallel sets of track and two skateboard wheels for the outer tracks or four sets for all tracks with a big plywood base?

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Two sets of tracks next to each other would be ideal. Yet our production budget and size wont allow for the required additional equipment nor man/womanpower neccessary to pull this off at this scale.

Have you heard of an adapter which allows to mount a stand onto an euromount ? This would benefit the stability greatly and i might have fewer issues with the light tipping over ...

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I'm not a grip and I don't know what a Euromount is, but I once had a key grip put a ladder on a western dolly with the camera on the ladder, so it's possible... but you need a wide base and/or a heavy base to counteract the top weight for safety. At this point, I really don't feel comfortable giving more grip rigging advice where safety is involved, you need someone on set who understands these issues.

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4 hours ago, Satsuki Murashige said:

Could you mount the 4K on a camera jib/crane? 

We probably could. But it would likely be too big to fit onto a GFM Quad Dolly (see image for dolly reference). In addition we dont have enough space to get the crane in a suitable position as the light isnt moving inline with the tracks... 

Out of curiosity, which type of crane would you use to get the 4kw up to a height of 4-5m ? 

Bildschirmfoto 2020-11-06 um 23.47.18.png

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4 hours ago, Montell Taraschewski said:

We probably could. But it would likely be too big to fit onto a GFM Quad Dolly (see image for dolly reference). In addition we dont have enough space to get the crane in a suitable position as the light isnt moving inline with the tracks... 

Out of curiosity, which type of crane would you use to get the 4kw up to a height of 4-5m ? 

Bildschirmfoto 2020-11-06 um 23.47.18.png

I was imagining something like a Jimmy Jib Triangle, which can hold a fair amount of weight at 18’, or about 5.4m. I think the max payload is around 50lbs (22.7Kg), so a 4K might be pushing it. It can extend longer at lower max payload.

A Technocrane would be ideal of course, but expensive!

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This might sound stupid. And it sure will look silly. But what if you underslung the 4k on a dana dolly and goalpost both ends with mombo combos? Then the combos can be saftey-lined from four corners. I'd advise from a grip on this idea.

Then it could be operated from below from a wooden platform, or a plank of wood spanned across two ladders.

Goalpost example below:

972091447_IMG_7606(1).jpeg.bff009c736bbba782763db065757069a.jpeg

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4 hours ago, Stephen Sanchez said:

This might sound stupid. And it sure will look silly. But what if you underslung the 4k on a dana dolly and goalpost both ends with mombo combos? Then the combos can be saftey-lined from four corners. I'd advise from a grip on this idea.

Then it could be operated from below from a wooden platform, or a plank of wood spanned across two ladders.

Goalpost example below:

972091447_IMG_7606(1).jpeg.bff009c736bbba782763db065757069a.jpeg

I think aluminum speedrail won’t be strong enough for the payload and such a long run. Even with steel pipe, you’re going to get a lot of flex on a run that long. I did a 20’ underslung pipe dolly shot with a Ronford F7 head, Amira, and a small prime lens last year, and the sag was significant with 1.5” steel pipe. I suspect a 4K HMI head will be heavier. You could try with ladder truss, but box truss would be better. 

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No, not stupid at all Stephen! Actually I thought about a similar setup but instead of using individual thrus pipes id opt for a long 4-point traverse. Using two wind-up stands on either side it would be easy to operate and the flex under load would be minimal. 
 

Yet I’m not too sure how to mount the slider upside down or how to safely mount the lamp onto it. 
 

 

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7 hours ago, Montell Taraschewski said:

Yet I’m not too sure how to mount the slider upside down or how to safely mount the lamp onto it.

https://modernstudio.com/products/adapter-mitchell-to-junior
I think the idea was to undersling rather than mount the slider upside down. You could use two Dana Platforms clamped together for a captive base. Or even better, use larger cheese plates and dolly skateboard wheels to widen the platform for more stability.

Of course, I’d defer to your gaffer and key grip on whether they feel this is safe. My sense is that this would be a lot more difficult to control one story up from the ground than your initial idea of putting the crank stand on tracks. 

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Yes. Safety is of uttermost priority. Got a meeting coming up where we'll discuss this in detail. 

Moving away from the whole idea of having the 4kw on any kind of track. Do you guys have an idea how to achieve similar effect using, lets say mirrors ? 

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18 minutes ago, Montell Taraschewski said:

Moving away from the whole idea of having the 4kw on any kind of track. Do you guys have an idea how to achieve similar effect using, lets say mirrors ? 

If you’re replacing the light with the mirror, doesn’t the mirror have to move along the same path? Or are you thinking of using a large static mirror and moving the light on the ground a shorter distance? 

My feeling is that effect will be quite different, unless the mirror is so large that it can span the same 10-12m distance.

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20 minutes ago, Montell Taraschewski said:

Actually im thinking about a way of not having to move anything on tracks altogether.... less moving parts = less room for error 

That would certainly make things easier. I don’t think you would get the same effect though, it would be more or less the same as panning the light around.

Another possibly bad idea - could you build a platform along the side of the building and lay track on it, so you don’t have to have the stand extended all the way? 

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If the sun moving across the room is illustrating the passing of time, you could consider time-lapse over the length of an actual day. Since sunlight is rarely continuous in most places, this could look more realistic. Just a thought.

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28 minutes ago, Satsuki Murashige said:

That would certainly make things easier. I don’t think you would get the same effect though, it would be more or less the same as panning the light around.

Another possibly bad idea - could you build a platform along the side of the building and lay track on it, so you don’t have to have the stand extended all the way? 

A platform would be nice but too expensive. 

 

@Uli Meyer "unfortunately" our windows are pointing towards the north and we only have one day on location...

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Have you thought about using scaffolding instead of a crank stand? It might be easier to get the height you're looking for while securing the scaffolding to the dolly track.

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Well if you want it moving in 3D space, that is different from pan/tilt from a locked position. Its the same as faking sunset by slowly dropping a flag over a light vs lowering the light behind a flag.

Mirrors. If you wanted a 3D move using mirrors, I can see an array of mirrors placed at your desired height (the angles must match), then placing a light on a doorway dolly on the ground and shooting up to the mirrors. This is a great way to get lights high like the sun without cranking the light  up there. You'll want to spot the beam so as much of it passes into the mirror. It will continue to spread upon exit like normal and from the set's point of view, it will appear high in the sky. This might be great because you could use several smaller HMI shoulder-to-shoulder, and clock the side lights a few degrees away from center to collectively act as a single point source. Again objectively from set, it  would be as if several HMI's were spotted in from far away. I imagine that full hampshire over each board will blurr the multiple sources as a single. At this point, the break in the boards would be the only limitation. A few branchasaurus setups might be desired to hide the breaks.

What about strapping the light to a golf cart? Or better yet, someone's open-back jeep. I'm sure those rollbars can be mounted to. Ora crank strapped in the back of a truck with the bed sandbagged? Your key grip is going to vomit to these ideas haha. 

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Put a very directional light on the ground, put a somewhat diffuse reflector on stands outside the window, pan the light along the reflector.

I recently wrote a piece on a show that simulated lights passing outside an aircraft cockpit in this way; they used an intelligent light to provide automated movement.

These reflectors were used in that case; they make long ones for just such a situation.

P

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This is what we did some years ago for exactly the same effect. We added some arms to the head to be able to pan the light while traveling.

It worked very well.

In these pictures we have used our BarTruss since we did not want to see the lightshake when passing a connection.

good luck,  Onno

 

 

IMAG1361.jpg

IMAG1364.jpg

IMAG1366.jpg

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