DIY Motion Control

[oneinfiniteloop]

Has anyone tried to build a diy motion control setup? I did a search and didn't see anything. Is there anywhere you can buy simple robotics that can be controlled by a comp (Mac). I'm guessing if you can buy a simple arm/dolly/motor/servo assembly that can be programmed you can make a simple motion control rig. I was wanting to build one for some miniuature shoots I want to do. Any ideas?

[oneinfiniteloop]

112 views and no one has any suggestions. All I'm really looking for is a robotic arm or something similar that can be connected to a USB port and control via software...I mean, LEGO has something like this, I'm sure there is somewhere I can get it?

[aegis]

google "servo controller".

you should find many, many usb connected controllers, some even come with memory and a pic onboard to "record" and playback the motions. Of course with a PC you'll have an infinate number of saved motions with a wired connection...

once the controller is in place your servos that muscle the weight around can be configured for either a certain range of motion (think elbow - 160 degrees) or a continous motion (think wheel - rotate 420 degrees, on an x" diameter wheel = y.z' of travel). Some of the more powerfull servos can provide several hundred ounces of force per inch which would allow you to rotate that heavy cam in either a pan or tilt mode.

Counterbalance the "arm" and you could easily provide a 3d space motion control. Here's where the PC really comes into play using one of those 16 port controllers, you would use a few for dolly motion. One for Arm pan, one for arm tilt, two more for the camera head and its independant pan and tilt.

Hope this helps.

[insanityfw]

It depends on what level of motion control you want to do. Rich Lee who posts on this forum did motion control on his mind-blowing music video and I believe he did it on a dolly with markings and manual moves, just paying close attention to the speed and such. I'm sure he was heavy into post production, so again it depends on needs and skill level.

[oneinfiniteloop]

Thanks Aegis for the suggestions!

I thought about manual motion control, but I'm primarily concerned with shooting mult passes of the same plate for compositing later on. Shooting difference mattes and stuff like that. It would be hard to get the pixel by pixel precision if the plates didn't match exactly. I'll have to so some tests once my model is built.

[aegis]

So are you planning on moving the model or the cam? Are you talking about stop-frame stuff or will there be motion?

[Greggl]

I thought about manual motion control, but I'm primarily concerned with shooting mult passes of the same plate for compositing later on. Shooting difference mattes and stuff like that. It would be hard to get the pixel by pixel precision if the plates didn't match exactly. I'll have to so some tests once my model is built.

Thats going to require some SERIOUSLY powerful and strong equipment. You cant afford any flex and the precision is extremely critical. I've done a decent amount of
work with mo-co plates and kuper data... its pretty hardcore and extremely expensive
to get even what I'd consider usable results.

What camera are you planning on using? You're going to want to shoot with
an HVX at the absolute minimum due to the variable speeds. Most motion
control is shoot at high speed or stop motion, computer controlled exposures.

What exactly are you trying to attempt? What is the requirement for miniature
work? Is it the models/modeling? The specific look? There are ususally 5-6
ways to skin a cat when it comes to VFX.

[oneinfiniteloop]

Well, originally I was planning on building a model of an exterior of a classroom. I need to do a shot where the classroom explodes, blowing out the windows and door of the room. I wanted to do a shot where the camera starts at the front of the class and swings around to where you are seeing the explosion from a profile view...

Taking into account the work that will actually go into doing mo-co, I might have to find another way.

[aegis]

Sweet - explosives!!!!!!!!!!! Shaped charges, propane, distruction....

Make sure to check out the example avi links
http://www.ri.cmu.edu/events/sb35/tksuperbowl.html

I'd say get 20 cameras, static mount um and mix video after the fact!

[oneinfiniteloop]

Hmmm, 20 cameras, eh? Maybe I should get 20 HVX's and use them...anyone want to help with funding?

[ilpoldo]

Hey, I'm doing some research too. I dropped the computer control, I'm thinking about something simpler, some kind of remote, a remote recorder (to repeat camera movement) and steppers, I found this: animatronics (http://www.milinst.com/animatronics/animatronics.htm) stuff . I'm pretty ignorant about this stuff, but sounds like it's worth a try what do you think? Sounds so cheap, what's wrong with them?

Just to be able to do repeated motion, I would miss time-scaled motion.