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Motion control cranes - silence required or not ?


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#1 Chris Millar

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Posted 15 December 2010 - 02:13 PM

Hello all,

So I've had a few good chances to play around with a couple of supertechno technodollys lately (yup, two different ones, lucky me)...

http://www.supertech...echnodolly.html

Its a motion control telescopic crane based on the technocrane line but with full motion control capability thrown in with the price tag.

Its all directly driven with pancake style or similar drives with very high torque ratings, this means it has next to no gearing (the auto horizon does have a worm drive however) - aside from that its all wire rope and pulleys... The noisiest item on it is the drag/cable chain (clak clak clak) which can be removed anyway and a sneaker wearing human cable pager used instead.

My question/s are:

- Do motion control rigs need to be silent anyway ?
- How often do you need to be sound synced when using one ?

Sure I can see how a programmable crane would be great for use in the usual crane sense - and also in the way that supertechno can use it in studio set ups ('matrix mode') - but I'm wondering if the technodolly is alone in the effort to make it so damn eerily quiet

How loud are other motion control rigs ?

Mark Roberts, etc...
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#2 Phil Rhodes

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Posted 15 December 2010 - 02:46 PM

In my fairly limited experience a Milo is fairly quiet until you start asking it to move quickly. Disconcertingly, certain types of apparently-gentle move can require unexpectedly rapid motion, particularly of the pan and tilt axes. Move any more than moderately slowly, though, and they create a fairly pronounced whirring sound of gears being ground together - which, by design, is what is happening.

The sound can be clearly heard in this video, although the dialogue is not in English.



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#3 Chris Millar

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Posted 15 December 2010 - 03:37 PM

hmmm, like most if not all things the technodolly doesn't like fast accel either.

It is pretty solid when it comes to its axes - as in there is usually only one way for the camera to be in any one position - except for the head pan and base pan...

The programmers in this instance have to decide on how the rig will deal with this and then the kinematics follows that paradigm. The technodolly at this stage is programmed via keyframing its actual real position in well, reality... So ambiguity in head pan and base pan angles (which affects the dolly position with respect to the head majorly) is dealt with by simply looking at where the dang thing is now anyway. Interpolation between frames can lead to impossible motion paths etc...

But theres nothing that cant be worked around once you understand how its set up.

(the milo on the other hand shows I think 2 axes of redundancy right at the beginning of that video, see how the camera is still but the rig is dancing behind it?)

Anyway, my main point is that the technodolly works at %100 speed always unless you dial it down - interesting way of working ! Its pretty much always going to be as noisy at it will ever be from the beginning. Some interpolations can result in axes compounding speed of the head (track + telescope / track + pan etc..) - which can result in a heap of momentum at long lever arms - you might get a creak here and there I think from any not fully firm/adjusted dolly track when this occurs...

WOW - just listened to the vid

like the comment says "f*ck its loud !!" - the technodolly is whisper cat compared, with the right set up and move its sync capable...

Interesting...

I guess my question is - is silence ever a consideration for motion control in narrative film or is it pretty much always overdubbed/sound designed as its a action/special sequence anyway ?


\\(forgetting virtual studio set ups like the technodolly has been used in, where for instance sports presenters are placed in a real time CG world)
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#4 Chris Millar

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Posted 15 December 2010 - 03:43 PM

any noise you hear here is completely the other rig:



Any idea what type it is ?
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#5 michael best

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Posted 20 December 2010 - 04:50 AM

A lot of the motion control cranes/dollies are used for effects shots or plate shots so sync sound is not super important. However some cranes/dollies are better for sync sound then other. However if you are doing any moves that require fast movments to sudden stops you will hear the gears and or the worm drive.

I think its Pacific Motion Control that does motion control dollies and cranes that are fairly quiet.
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#6 Stephen Williams

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Posted 20 December 2010 - 04:32 PM

(the milo on the other hand shows I think 2 axes of redundancy right at the beginning of that video, see how the camera is still but the rig is dancing behind it?)


Hi,

The Milo has 'Master' axis that work with target tracking, being able to move the rig & keep the camera still can be very useful when bits of the set are in the way or to move the rig to avoid shadows.
A few Milo's were originally delivered with a fixed arm, however I think they all got upgraded. If you do a lift then to keep the camera the same distance from the object the arm needs to move.
When you tilt the camera down to the floor you loose the ability to 'Pan' by being able to move the rig say 20 degrees clock wise (keeping the camera still) pan is then restored! The rig can do some fairly complicated moves to avoid getting 'stuck'. All those axis are needed!

Stephen
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#7 Chris Millar

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Posted 20 December 2010 - 06:31 PM

hmmm,

interesting - sort of a possible gimbal lock situation ?

I'm reasonably serious about building a decent home brew system - something that once built could with a bit of investment go on to work along side these big $$ systems.

I know I'm not the first and the internet is riddled with examples, but I feel they tend to be one trick pony rigs, nothing wrong with that of course, but I think with time there will be a distillation of ideas and requirements that maybe one or two archetypical styles of 'almost do all' rig will eventuate - I'd put a small wager that something like the technodolly is one of those.

I had the privilege of having a look see of the technodolly prototype recently and although it had an obvious supertechno feel about it, it was a different beast in that the idea was it could do full tilt revolutions as well as pan. Lots of issues to deal with, especially in the auto-horizon department and cabling, so I think the call to bring the technodolly as it stands to market much sooner was wise, but now that cameras are getting lighter (although there is that pesky doubling of weight in 3D) and wireless technology is plowing ahead that maybe a smaller system where the issues with this prototype may scale down to something solvable.

Another topic but there is also the issue of the camera not being able to be in the place of the rig, so I was considering a XY table system that the rig could sit on on the dolly itself (or a studio mounted gantry) - that way you avoid that 'sphere' of no-go in the middle of the rig, lots of kinematics/coordinate math issues to deal with for a layperson, but its no fun without a challenge huh!

I guess, to answer my question - no, silence isn't required - but can be helpful in specialist situations.

I'd like to know from actual motion control users / operators what they feel about the rigs themselves - mechanically that is - what different means of articulation mean in real world situations...

I hadn't considered rig shadows - of course, it'll be an issue - and its the kind of thing I need to know about
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#8 Stephen Williams

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Posted 21 December 2010 - 06:57 AM

I'd like to know from actual motion control users / operators what they feel about the rigs themselves - mechanically that is - what different means of articulation mean in real world situations...

I hadn't considered rig shadows - of course, it'll be an issue - and its the kind of thing I need to know about


Buildings rigs is expensive, there are no economies of scale & you will have to re-do everything several times to get it 'better' it's never 'perfect'

I know ILM spent more than a $1,000,000 developing their own card for a PC, in the end they settled for one from 'Cooper' for $1000.

It needs to be very rigid, light, able to accelerate fast, portable, reliable.......... I know several people who went bust doing exactly this.........it cant be that diffiult! Bear in mind there are about 40 Milo's world wide, they were 36 in 1999! It's a tiny and shrinking market.
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#9 Phil Rhodes

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Posted 21 December 2010 - 08:36 AM

I keep thinking about strapping some mechanics to my dolly so I could at least do repeatable dolly moves - perhaps a bit more of a realistic first step.
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#10 Stephen Williams

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Posted 21 December 2010 - 08:53 AM

I keep thinking about strapping some mechanics to my dolly so I could at least do repeatable dolly moves - perhaps a bit more of a realistic first step.


Thats probably very worthwile, keep it simple & you wont go far wrong.
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#11 Chris Millar

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Posted 21 December 2010 - 02:37 PM

I know about the costs - at least i think i do ...

What I've been doing is building a VMC style CNC machine (computer numeric controlled vertical machining centre) - most of the expensive parts involved in it (linear bearings, BLDC motors, ballscrews if I decide to use them) have been dual specced in that they can find use on a moco rig, I know its bit chicken and egg in that the CNC mill will be building it, but go figure...

I also work in theatre automation, which is pretty much cine motion control but instead of putting a camera on the end we put set pieces and people - sometimes huge stuff - complete stages etc... Whatever I do I feel that it'll be skills learned, and I can probably get a favour here and there with parts and fabrication (gawd I hope the guys aren't reading this! :lol:)

But I do hear you - business mentor alarm bells must ring when I say that it's a hybrid hobby/business project.Those Milo numbers are interesting - although it doesn't argue a point either way I can add that since the technodollys inception I think there are around 8 of them out there, it has a €625,000 price tag.

Question: could it be thought of this way - Milo sales are dwindling not due to market saturation, but due to obsolesce - not so much in the face of a clearly better design but simply the desire for something better ?

What I'm trying to distill is the essence of what would make a rig better - or more succinctly, a completely better rig...

I need users input
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#12 Stephen Williams

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Posted 21 December 2010 - 03:11 PM

I know about the costs - at least i think i do ...

But I do hear you - business mentor alarm bells must ring when I say that it's a hybrid hobby/business project.Those Milo numbers are interesting - although it doesn't argue a point either way I can add that since the technodollys inception I think there are around 8 of them out there, it has a €625,000 price tag.

I need users input


Hi,

You build once, then throw it all away as the bearings vibrate etc, build again etc etc.

A Milo can be bought new for Approx £200,000 / 240,000 Euro . Speed of Axis, type of track. cameras etc will add more. I know of one in pretty good condition that sold for $100,000.

There is way less money in the business as you think, if it was easy lots of companies would make them. Viewfactor Studios took some deposits.......

When you have built the rig, you then need to write the software, Mark Roberts spent several years getting everything to work in the late 70's, I was a client waiting and waiting....
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#13 Phil Rhodes

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Posted 21 December 2010 - 03:40 PM

And frankly from what I've seen, the software ain't all that. Bear in mind that software (with things like Java and .Net), and hardware (with microcontrollers like AVR) are now much, much, much easier than it ever was before.

But having a set of bearings and having a motion control rig are rather far apart.


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#14 Onno Perdijk

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Posted 21 December 2010 - 04:11 PM

Hello All,

As many others I have been thinking of finding a way to do MoCo easier and cheaper. but....

1) the difference between MoCo and Repeatable: If you are thinking MoCo you need keep a constant link with the camera-shutter / mirror / sync; so a move is always made in steps of 1/24(25) or the regular variations.
2) millions have been spend on developing different systems and even the existing brands still are still spending thousands!!!
3) every machine/robot has his own specifications/ downsides/ advantages, you cannot satisfy all customers.
4) ofcourse it is fun to do the machinery to make your own rig, ofcourse it is a joy to rewrite and reuse the software but I have found that it is not worthwhile.

a) however; I made myself a repeatable rig for tracking only, no panning, no tilting. That already took me some time
B) money in this biz is less and less. lets not go cheaper in gear but more cost-effective and combine our strength. ( a plumber can do his work in my house within three hours for 180 euro's, I myself would spend a full day and have some materials unused and unreturnable...) so: put your money where your knowledge is...

Meanwhile: I would encourage anyone in experimenting and trying to create solutions since a lot of good things came from there!!!

K.I.S.S. Keep it stupid simple

Good Luck

Onno
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#15 Chris Millar

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Posted 21 December 2010 - 04:22 PM

You build once, then throw it all away as the bearings vibrate etc, build again etc etc.


Yes - although, I'm not sure about 'throwing it all away' - I'm not going to be using much glue!

There is way less money in the business as you think, if it was easy lots of companies would make them. Viewfactor Studios took some deposits.......


You're wrong, not in that the ship sailed a loooooong time ago - but in that I wasn't aware ;)

When you have built the rig, you then need to write the software, Mark Roberts spent several years getting everything to work in the late 70's, I was a client waiting and waiting....


See below - ;)

And frankly from what I've seen, the software ain't all that. Bear in mind that software (with things like Java and .Net), and hardware (with microcontrollers like AVR) are now much, much, much easier than it ever was before.


But having a set of bearings and having a motion control rig are rather far apart.


Yeh, sure - of course - but all it is is an integrated system of parts of which I'm aware (maybe not some of the comms protocols actually, but it seems like there's nothing too proprietary going on in the examples I've seen, RS232/435 etc...) - any trickery just needs to be seen as an isolated project to solve, sure some of these will take a lot longer than intended, but then others will relatively arbitrary and will balance the scales. I have no illusions that the concept in my head is not without its missing parts and there will be hurdles... Its not like I don't have experience either, but thats not my concern, nor it need be yours or Stephens, but thanks for the advice, I maybe seem defensive and blinded because of it, but it is truly appreciated. That being said maybe I expect too much from the forum here ( :rolleyes: ?) I remember the 'new super8 camera' thread, where even I was critical of the premise of the thing. Compared to that idea I think there are legs in cine moco, the techodolly use in virtual studios is a good example of how the process has been applied in a new way (well, new compared to the 80's/earlier 90's) - without its inherent silence, which seems to be unique (?) it couldn't have been done anywhere as effectively.

If it helps push me into the 'some people will never listen' territory - then I'll say this: I see it as an art project :ph34r:

Still I ask: Without resorting/alluding to knowledge of the problems and complexities involved in a solution - what would you like a motion control rig to do that no one currently available can deliver ?

Toast sandwiches ? I've seen one recently that could have done that actually (longish story I shouldn't claim to be privy of, but I'm actually not kidding :lol:)
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