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DMX - Smooth Operation?


TechnoRocker

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Hi guys,

 

I'm really baffled with this one. Got my scanners out again recently and decided to have another play with them. I've been watching a lot of videos on light shows mainly mobile discos with scanners ect.

 

My question is, how do people get their scannners to move slowely like in this video? Can you only do that with a computer or can it be done with a DMX controller?? When I program my lights, they seem to just move step by step and it all seems very 'blocky' and 'stiff'.

 

How can I get a fluid motion to my scanners? I have 4 channel units, with a 16 channels DMX controller. Can it be done or not - it's driving me nuts!! :)

 

Many thanks in advance,

Adam

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Simple controllers do not offer the full functionality of the bigger pro controllers with shape generators and slow movement calculations built in. You will possibly need to look at programming lots of small steps. or getting a much better controller.
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Even with the right controller, it won't happen. Your scanners only have 8-bit pan and tilt channels (ie: 1 DMX channel per attribute.) That only allows for 256 steps. The scanners you wish to emulate have 16-bit control, which mean they use two DMX channels per attribute, which allows 65536 steps. There's more info here.

 

So, sadly, you'll need to replace pretty much everything before you can get it that smooth....

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You would not need 16bit to get movement like that and you don't need shape generators either.

 

All you need is to have fading capability. If the desk fades between each position (usually in a chase) then you will get this effect. This is how it used to be done and it always worked marvelously.

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I would have thought that it's just the desk that needs to be looked at here, surely the scanner allows you to move the mirror/beam around fluidly with manual control.

What desk are you using?

When you program your chase are you able to change the amount of time it takes between each step? Can you control the crossfade (sometimes called X-Fade or Slope)? It's the crossfade that will allow the 'fluid' motion you talk about.

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You would not need 16bit to get movement like that and you don't need shape generators either.

 

All you need is to have fading capability. If the desk fades between each position (usually in a chase) then you will get this effect. This is how it used to be done and it always worked marvelously.

 

 

The console can fade all it likes, but if there's only 256 possible positions in each axis, then a slow fade will look "steppy". Obviously, that depends on your standard for what is acceptably "steppy" and what isn't.

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Hi everyone.

 

Thanks a bunch for all your input. I do hope you can help me conquer this beast!! :)

 

The DMX control desk I have is a Thomann.de special. It can be found by clicking this link. It does have a fade capability but I've been playing around with it and it just makes the lights move a tad slower between the steps at a speed which I can change using a speel knob.

 

How can I make my lights for example tilt from the floor to the ceiling very slowly, then on the next step make a sequence of gobos fast move around the room?

 

Sorry, I probably don't make much sense. I have my scanners out at the moment, I may take a video on my mobile phone - sorry it's the only fast FPS cam I have...

 

 

Many thanks,

Adam

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The console can fade all it likes, but if there's only 256 possible positions in each axis, then a slow fade will look "steppy". Obviously, that depends on your standard for what is acceptably "steppy" and what isn't.

Sure, if they were going very slowly, but at the speed shown in the video or anything similar this will not be an issue. I have used plenty of 8-bit scanners in the past on various consoles and never had any noticeable problems, even at relatively low speeds.

 

How can I make my lights for example tilt from the floor to the ceiling very slowly, then on the next step make a sequence of gobos fast move around the room?

I can't comment on how you might do this on that desk, if it's possible. But you would want to create a chase where each step had the position and gobo information as required and have it fade between each. If the fading for the movement affects the way the gobos change then you might need two separate chases - one for position (fading) and one for gobos (snap).

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Hi everyone.

 

Thank you for all your replies. I managed to have a play around with the scanners and the desk and came up with this video below. I had the fade time on minimum so basically I enabled the fade time but then made the steps as close together as possible. Unfortunately my DMX desk doesn't have dedicated controls for speed and fade time. Instead, it has a button you press to switch between fade and step using the same speed knob.

 

To see the video, click here. I posted the vid on my website.

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I have a pair of Acme Dynamos which do the same thing. They only have about 16 steps of movement on each axis. What I believe is happening is although the lights are being fed with a 8 bit control signal (In my case from MagicQ PC) this is being dumbed down by the processing in the Light itself and fed to the steppers at a lower resolution. This only happens with DMX control as the built in programs don't need to be processed from DMX into control commands for the steppers.

 

Josh

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Do the lights have a light to sound/Automated function? Might be worth seeing if the scanners can scan smoother, They must be able to move to more positions that shown in that video!

 

Hi Richard,

 

Yes the scanners can move smoother than that but I have personally programmed them via my DMX desk. It's not easy programming a curcular motion such as that shown in the video.

 

Also, when creating steps for the sequence I made, I found that when creating a new step the light will default all DMX channels (1-4) back to 0 even though the faders are set to a value. I have to move the fader to make the scanners react. Maybe I'll make a video on that too one day. It's hard to illustrate what I mean in writing...

 

Any ideas?

 

Many thanks,

Adam

 

A concurrent post has been automatically merged from this point on.

 

Also I forgot to mention, in the video the scanners move slower than it does at the end. This is because I turned down the fade time between steps. I wanted to see if the smooth motion went away and unfortunately it did. I know this can be done - just wait til the end of the video and you will see the sequence at minimum fade time ;)

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