Mutlitple webcams

Community Forums/Developer Stations/Mutlitple webcams

Nebula(Posted 2003) [#1]
I am looking for a setup to capture 'accurate' 3d animations using multiple webcams.

What kind of 'cheap' 3d modelling program is best suited for this kind of animation. It needs to be able to easily load images to preferably multiple viewports.

Also what kind of pc specs would I need to capture 3 video streams?

I am not going to capture 3d animation, I am just checking for options.


Russell(Posted 2003) [#2]
Nebula, I'm confused. In your first sentence you say 'I am looking for a setup to capture 'accurate' 3d animations ', then in your last sentence you say the opposite: ' am not going to capture 3d animation'. Let's assume you do:

When you say '3d animations', are you talking about steroscopic animations (requiring special glasses to view) or are you talking about motion capture data obtained from live actors?

If the first one is what you mean, then, in theory, you only need two cameras (one for the left eye view and one for the right). But for best results the cameras would have to be perfectly snychronised, if you're capturing 'live' video...and that's not so easy to do. If the video is generated by a 3D computer program, then the stereoscopic images can be created automatically if the program supports it.

If, on the other hand, you're talking about getting data to create 3D models by using multiple cameras, then it gets MUCH more complicated, although there ARE programs out there that can create models from photographs. (Try ftp://ftp.nsk.su/.3/windows/graphics/pmlt31a.zip for a free version of PhotoModeller - normally $895!)

Motion capture is yet another complicated task, whereby 2 or more cameras are used to obtain 'skeleton\bone' movement from live subjects wearing ping-pong balls with reflective tape at key positions on their bodies. It IS possible to get very good motion capture using only one camera, but requires a lot of patience and a 3D program that supports constraints and Inverse\Forward Kinematics...

Good luck!
Russell


jfk EO-11110(Posted 2003) [#3]
If you find an app that supports 2 Cams at the same time then please drop me a line. If I once got their images in Blitz the mocap is incredibly easy to obtain.

But in fact I even have an Idea for 3D Mocap with only one Camera and a big mirror:

               /
       actor  /
cam<         /
            /
           /
          /Mirror


But of course - this is only a very limited motion capture.

When it is really such a problem to rum 2 cams in the same time on one Computer, then it might be the simplest solution to use 2 Computers with one Camera each and a Connection over a Port, the parallel Port for instance, to send Syncing Signals. You know, use that old 266 something MHz Machine. Might be even cheaper than a Mirror.


Nebula(Posted 2003) [#4]

Nebula, I'm confused. In your first sentence you say 'I am looking for a setup to capture 'accurate' 3d animations ', then in your last sentence you say the opposite: ' am not going to capture 3d animation'. Let's assume you do:



What I ment was that I am not going to try this any time soon. Atm, I find it more fun to make 2d animations out of captured video.

When you say '3d animations', are you talking about steroscopic animations (requiring special glasses to view) or are you talking about motion capture data obtained from live actors?



capturing motion, yes.


When it is really such a problem to rum 2 cams in the same time on one Computer, then it might be the simplest solution to use 2 Computers with one Camera each and a Connection over a Port, the parallel Port for instance, to send Syncing Signals. You know, use that old 266 something MHz Machine. Might be even cheaper than a Mirror.



Recording with 2 cams should already be possible when running windows media encoder twice. But atm I have no money for another webcam or a usb hub to test this.
And ofcourse I can always use a other pc.

btw - I find that the syncing process is unimportant when filming. You can sync it later with vdub. Currently I can use one webcam for getting the 3d movement, but it requires identical movement and takes more time.


jfk EO-11110(Posted 2003) [#5]
I even have troubles getting one camera picture into blitz... a lot of soltuions but none works properly.

I think I go back to the webcam sever and use it via loadmovie over a localhost http connection. I'll post it here if it works.


Russell(Posted 2003) [#6]
Here's an easier way to sync two separate video streams: Use two separate video cameras (or possibly two camera\computer setups) and have a single chronograph visible in both views. Then trim one of the videos in Premiere or VirtualDub or whatever so that they start on the exact same frame (by looking at the chronograph). Ideally, the chronograph would have a sweep hand that measures 1/60 of a second. Finding one large enough to be seen in both views is the tricky part...

Once you have that, then the fun part begins :)

Russell