# How is this effect achieved?



## microfusionwelding (Dec 2, 2010)

Just curious to how this effect is done. It's a clip from the latest TSO tour. Right past the 2 minute mark you'll notice the darkened shadow effect on lasers. Just wondering how this is done? 

YouTube - TSO-First Snow


Thanks
Dan


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## gafftaper (Dec 3, 2010)

When the laser is a really narrow beam you can see it in the air no problem. When they fan the laser out wide then it's harder to see without hitting some sort of particulate in the air (fog or haze). About 1:40 you see a bunch of dry ice fog creeping it's way across the stage. Unlike all the haze that is already in the air, that dry ice fog is unevenly distributed and more like clouds. When the fanned out laser hits the fog it really pops. Where it doesn't hit fog it looks like it's in shadow.

Welcome to Control Booth Dan! Please stop in the New Member Board and introduce yourself... and thanks for the video link. I've got a 6 year old who is going to freak out when I show it to him.


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## Les (Dec 3, 2010)

Dan,

Welcome to the booth! 

I see what gafftaper is referring to, but am I correct that you're talking about that wave effect right at the 2 minute mark? That's much too uniform to be a mixture of haze and dry ice fog. 

I'm curious about this effect too. It seems to defy logic.


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## skienblack (Dec 3, 2010)

Les said:


> Dan,
> I see what gafftaper is referring to, but am I correct that you're talking about that wave effect right at the 2 minute mark? That's much too uniform to be a mixture of haze and dry ice fog.
> 
> I'm curious about this effect too. It seems to defy logic.


 
I would agree that there has to be something else thats in the air besides haze/dry ice fog. Could they ever be using something like a series of snow machines? I feel like that would allow for the falling effect and still potentially break up before it hit the audience.


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## gafftaper (Dec 3, 2010)

Les said:


> I see what gafftaper is referring to, but am I correct that you're talking about that wave effect right at the 2 minute mark? That's much too uniform to be a mixture of haze and dry ice fog.
> I'm curious about this effect too. It seems to defy logic.


 
Wow Les I hadn't even noticed that at first. It's only there from about 2:01-2:07 A curling wave of shadow, most visible on the farther reaches of the beam. I was originally looking at the clouds of fog at the center of the shot, and didn't see it. Yeah that pretty much defines the laws of physics in my head. It appears TSO has developed the ability to temporarily alter the speed of light.

I wonder if it's an optical illusion created by the lasers all being in the same plane and panning through each other while they gradually moving one "shaft of darkness" across the stage and back. The curved wave thus being just a solid shaft of black that is having the curve part filled in by the overlapping lasers from other angles. Words kind of fail to describe this don't they?


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## sk8rsdad (Dec 3, 2010)

My guess is it's a moire pattern formed by the lasers diffusing through the haze. I think it might be a fluke event in this video. I would think if it could be reproduced at will then it would have been used more frequently. It is possible to build a rig to deliberately produce moire patterns. This picture is from a research paper on techniques for examining solder joints.




And this is some guy playing around with a pocket laser and a butane lighter.


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## microfusionwelding (Dec 3, 2010)

sk8rsdad said:


> My guess is it's a moire pattern formed by the lasers diffusing through the haze. I think it might be a fluke event in this video. I would think if it could be reproduced at will then it would have been used more frequently. It is possible to build a rig to deliberately produce moire patterns. This picture is from a research paper on techniques for examining solder joints.
> 
> 
> 
> And this is some guy playing around with a pocket laser and a butane lighter.


 
Found a show which was recorded 9 days later at a different venue and also a different angle. The effect is still visible here as well, right around 1:50. Any clues?

YouTube - First Snow - Trans-Siberian Orchestra


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## microfusionwelding (Dec 3, 2010)

Don't think it's a fluke. Found a different show at a different venue. Look around 1:50. Any clues?

YouTube - First Snow - Trans-Siberian Orchestra


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## epimetheus (Dec 3, 2010)

I don't believe this is a fluke either. I've seen TSO for the past couple of years and I wouldn't be surprised that they can accomplish an effect such as this. I'm betting that this is well within the capabilities of the laser units they use.

Anybody from the TSO organization on CB willing to educate our curiosity?


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## len (Dec 3, 2010)

I watched it a couple times and it looks like it's in the video screens to me. Just another layer of video effect. I'll bet they use the same effect but a different pattern.


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## epimetheus (Dec 3, 2010)

Are we not talking about the shadowy arcs that move through the laser field?


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## microfusionwelding (Dec 3, 2010)

epimetheus said:


> Are we not talking about the shadowy arcs that move through the laser field?


 

Yes, those are the areas we are discussing.


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## soundman (Dec 3, 2010)

To me it looks like the 'cone' effect you get from a ring gobo. The interesting part of it is they can control where the light starts and stops. Perhaps it is an effect with in the laser, Instead of being parallel it angles them together and they dross paths in mid air. Kind of like turning the ring into a very shallow ellipse.


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## Les (Dec 3, 2010)

I would also say that it doesn't look like a fluke. Several of the units do it, and it's a very uniform sweep. I don't think it's video - it looks to be mid air. The ring gobo is an idea, but usually you get a straight shaft of shadow. It's been a while since I've read up on diffraction gratings, liquid sky and such. 

gafftaper, you crack me up!


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## WooferHound (Dec 3, 2010)

It looks to be an artifact from the Video Camera to me. I don't think you would have seen that standing in the audience.


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## microfusionwelding (Dec 3, 2010)

WooferHound said:


> It looks to be an artifact from the Video Camera to me. I don't think you would have seen that standing in the audience.


 
I don't know, I got video from 2 concerts at 2 different venues 9 days apart and from different angles. It is the same on both clips. My reply which is post #7 has a link to the second clip. Take a look it's right around 1:50.


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## DuckJordan (Dec 3, 2010)

It looks like a special gobo in a gobo-rotater to me...


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## kendal69 (Dec 3, 2010)

I can't help with that effect, BUT WOW was that an amazing show. It was almost 3 hours and I have never ever been to a better concert that that one. They went with a lot more lED this year than in the years past. Fewer light but a better show.


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## Les (Dec 4, 2010)

DuckJordan said:


> It looks like a special gobo in a gobo-rotater to me...


 
Except that it directly interacts with the laser. And lasers don't do gobos. Just makes me (and everyone else, apparently) wonder, how do they get that curved beam effect?

I don't think it is a video camera artifact. It appears very deliberate and happens with several units on two different shows.


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## MNBallet (Dec 4, 2010)

Les said:


> Except that it directly interacts with the laser. And lasers don't do gobos. Just makes me (and everyone else, apparently) wonder, how do they get that curved beam effect?
> 
> I don't think it is a video camera artifact. It appears very deliberate and happens with several units on two different shows.


 
It is in the laser units. That effect is done several times during the show. You can see it better in a clip of the "Mad Russian" song. The effect goes on longer in that one. How it is done I don't know, but I bet it has several steps in creating it with several mirrors and motors. If you think about it as a concept that a lighting design is saying where light is supposed to be, the opposite is true that you are also designing where the light will not be. I've been told that a really good light designer is more of a shadow designer.

Ken Pogin
Production / Tour Manager
Minnesota Ballet


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## Pie4Weebl (Dec 4, 2010)

A guy I work with owns a laser company and I e-mailed him the video asking what the effect was, he responded with this:

Shawn said:


> "The Effect you are talking about is not an "efect" but is how the camera sees the laser the laser fans are being scanned at apox 30k -50k points per second the darkened waves are just the camera picking up the scan pattern making it seem to have a darkened effect."



Since all cameras work the same it doesn't surprise me that it would show up in multiple videos.
COHERENT LASER ENTERTAINMENT - Flash Intro


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## Les (Dec 5, 2010)

WooferHound said:


> It looks to be an artifact from the Video Camera to me. I don't think you would have seen that standing in the audience.



Ding Ding Ding!!!

And I stand corrected!


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## chausman (Dec 5, 2010)

So if it is just from the video camera, why do we not see it at other times in the video? There are times before and after 2:00 and it doesn't show up.


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## Pie4Weebl (Dec 5, 2010)

chausman said:


> So if it is just from the video camera, why do we not see it at other times in the video? There are times before and after 2:00 and it doesn't show up.


 
This is only conjecture, but my thought is there are certain variables that have to line up for the effect to be seen. I imagine it only works out when the beam is doing a wide enough spread that it can't make it across the full beam in one frame of the camera image.


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## FatherMurphy (Dec 6, 2010)

The answer, if it is camera-related, might be similar to the way that wagon wheels and airplane propellers sometimes seem to reverse themselves in old movies, as the spoke/blade positions change speeds relative to the shutter speed.


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## skapp (Jan 11, 2011)

I've worked in Ohio and PA with TSO and know the laser and pryo guys. I have worked directly with the Pyro Crew Chief Tristan Ford, Pyro Tech Jan Sanderse, and EFX Tech Simon Brierley. The Pyro Company (Pyrotek Special Effects Inc.) and the Laser Company (Laser Design Productions) is owned by the same parent company so I have also spent a good bit of time working around and talking to Laser Crew Chief Jason McEachern. 

To clear up the misconception, they do NOT use dryice fog. As a matter of fact what looks like dryice fog isn't fog at all! 

The fog often gets a swirl in it from the house HVAC or the fans in the truss that shove the fog downwards. Combine that with the way cameras capture laser you get what is seen in the videos. 


In 2009 they used the following on the tour...
Two 10 watt Full Color DPSS/Diode Laser (Center Stage & FOH)
Four 5 watt DPSS KTP NdYag laser
Six LDP 10 Projectors
60 Bounce Mirrors
Pangolin Control Software 

2010 was close to that..just more of the 10w full color lasers but I can't find the official list right now. 

More info might be available on their website at Laser Design Productions a few of the Gallery images from the 09 tour on their site shows the swirls in the fog as well.


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