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-   -   What is Rotoscoping? (https://www.dvinfo.net/forum/techniques-independent-production/5564-what-rotoscoping.html)

Jim Wiggins December 18th, 2002 01:54 PM

What does the artist mean when he used the technique called "rotoscoping" and why is there so much work involved?

Thanks for your time

Jim Wiggins

David Mintzer December 18th, 2002 02:00 PM

It is literally drawing or painting on video or film---frame by frame--that's why it is so time consuming---

Jay Gladwell December 18th, 2002 02:01 PM

In computer graphics, to rotoscope is to create an animated matte indicating the shape of an object or actor at each frame of a sequence, as would be used to composite a CGI element into the background of a live-action shot. 2. Historically, a rotoscope was a kind of projector used to create frame-by-frame alignment between filmed live-action footage and hand-drawn animation. Mounted at the top of an animation stand, a rotoscope projected filmed images down through the actual lens of the animation camera and onto the page where animators draw and compose images.

Robert Knecht Schmidt December 18th, 2002 02:55 PM

Disney's Snow White was rotoscoped from frames of a live actress!

Peter Moore December 18th, 2002 05:02 PM

When fan-films make lightsaber sequences, that's exactly how it's done - you draw white blades over the live blades on the film and then apply glow effects to make it look real.

Jim Wiggins December 19th, 2002 10:59 AM

Thank you!
OK. I have heard of this before. Is there software that will track an image within a frame throughout multiple frames and apply the glow effect or whatever to that image. (apply effect to one frame and the software can "follow" the image, generating the special effects over multiple frames)

Peter Moore December 19th, 2002 02:08 PM

I don't think so. You could possibly accomplish this with a blue-screen type technique where the object you want is totally bluescreened (or wrapped in blue) so you can isolate it from the image, but how this will appear in practice I don't know. When you look at raw footage of a lightsaber fight, the blades are often hard to distinguish, especially when there's fast motion. I doubt even bluescreening would make up for this. I think you're going to have to do it the old fashioned way, I'm afraid.

Brian M. Dickman December 19th, 2002 02:43 PM

You got it Jim. Most of the time this is just done with 2D point tracking, doing a combination of intelligent software driven tracking, and human binary search until things match (move halfway from start to finish, fix the points, move halfway from that, fix...). Pinnacle's Commotion Pro is a very popular rotoscoping package, and to some degree the same kind of things can be done in After Effects. Some of the more complex packages can track in 3D as well, so you can let the computer do some of the more complicated work like object rotation.

If you're more interested in the effect, you might check out www.dvgarage.com. A lot of digital effects experts hang out in the forums there, and the site also has some great effect tutorials, including a multipart on compositing where the instructor uses AE to add sabre glow.

Robert Knecht Schmidt December 19th, 2002 03:15 PM

Compositing questions for the experts
1) I have a piece of footage with two people crossing into and out of frame. I need to isolate the people from the background behind them. The camera is perfectly static and nothing else in the frame moves besides the people, and since the people move into and out of the frame completely, I have an image of just the background. Is this enough to make a matte that isolates the people from the background without rotoscoping the people? A difference matte doesn't quite seem to do the trick, but perhaps a difference matte in combination with something else...? One complication is the people do leave shadows on the background as they go by...

2) If I have to rotoscope the people, how should I handle portions of high motion blur wherein a body part's edges are indeterminable and parts of the backrgound show through the fast-moving body part?

Barend Onneweer December 19th, 2002 03:50 PM

Difference matte is a fantastic concept, but I've rarely seen it work, and you'd need perfectly clean material to get usable results. And with the shadows cast on your wall, I think your looking at a rotoscoping job...

If you use After Effects or Commotion to mask out the moving people, you can actually apply motion blur to the masks, tweaking the shutter angle in AE to get the right results. You could also manually feather certain masks, since I recommend to create separate masks for upper arm, lower arm, upper leg, etc... But manually keyframing the feather is a pain, and the motionblur often works great. Good luck...


Jim Wiggins December 19th, 2002 04:03 PM

Thanks again!
Brian, thanks for the link! Software application specific - just what I was looking for...

Jim Wiggins

Jim Steffel December 31st, 2002 01:18 PM

I have used Combustion 2 to track masks of moving objects in a scene. The computer does much of the work. However, the final tweaking, the detail work, is very tedious. I have also used Combustion 2 for green screening and/or keying. This work requires a great deal of effort and attention to match the lighting of the two (or more) scenes being composited. Admittedly I am new to most of this, but to me it is a toss up.

Robert Knecht Schmidt December 31st, 2002 01:50 PM

Out of curiousity, jsteffel, what tool is used in Combustion to do the auto-tracking? Is there a tutorial or something on the web just so I can see what this sort of process looks like? Especially, I'd like to know how it is possible to get good masks of objects that have motion blur in a frame (fast moving legs and arms and such).

Jim Steffel January 2nd, 2003 08:28 AM

Rapid, complex movements are not easy to track. They would require frame by frame editing. Tracking moving objects, such as a vehicle or a ball, can be done with little or no frame by frame editing. Complex movements like figures fighting or dancing would better be done with green screening or keying.
Keep in mind I am a relative newcomer to Combustion.
Also, the Combustion tracker can take out some camera jitter by stabilizing the video using reference points.
This link might better explain some of Combustions features.

Robert Knecht Schmidt January 2nd, 2003 11:24 AM

Alas, all the links on that tutorial page are broken--it's useless.

The closest thing I could find was
but this doesn't offer the keying tutorials that looked interesting.

If anyone has these files saved to their hard drives somewhere, do pipe up...

Jim Steffel January 2nd, 2003 03:18 PM

Sorry about that. Discreet seems to be making it difficult to get info on Combustion.
There is not a lot of written instruction on Combustion. In fact there are no books available.
There is a free demo available from Discreet.

Marc Betz January 4th, 2003 08:01 AM

Hey Robert
How good is your internet connection? I can try to email you the tutorial file from Combustion2. It is a 13.5 MB PDF file. Also the help files are navigate-able HTMLs at about 30 MB.

Let me know if you want em.

Marc Betz January 4th, 2003 08:08 AM

I zipped em
So they are now 16.5mb HTML and 11.5mb pdf.

Let me know....


Peter Koller January 4th, 2003 04:55 PM

Hi Marc, just in case you have a little bandwith left..

could you email the stuff to me, too? ;-)


Thanks a lot!

PS: Do you mean the Help Files that come up when you hit F1 in Combustion? Donīt need them. Just the -pdf then.

Marc Betz January 5th, 2003 08:21 AM

The files I have are what came with combustion2. If you have combuction 2 installed and you go to /program files/discreet/combustion2/tutorials/ and look at combustion tutorials.pdf. It is about 14 mb 11.5 ZIPPED. If you don't have this file, I'll send it right along.


Bob Deming January 5th, 2003 01:06 PM

Check rotoscoping out here


Robert Poulton January 6th, 2003 01:10 AM

Hey you need to goto www.dvgarage.com they have the best information on this subject and have a good forum. They also have a compositing toolkit that shows you how to make lightsabers in AF (After Effects).


Peter Koller January 6th, 2003 06:40 AM


No, I donīt have the tutorials. Please, pretty, pretty please mail 'em! p.koller@kabsi.at

Marc Betz January 6th, 2003 07:14 PM

Hey Peter
Check your email inbox...

Hope thats what you needed.

Aaron Nanto January 8th, 2003 05:25 PM

Combustion stuffs...
Actually commenting about no books being available for Combustion, there are actually a few books out:

Combustion 2 Courseware from Autodesk Press
(However I'm not sure if you can get this without being a student)

Discreet should still have a few tutorials on their site from the courseware which are very informative (sorry if this was already brought up)

Marc Betz January 9th, 2003 04:54 PM

Hey Peter
Were the files I sent what you needed?

Alexander Pruss October 23rd, 2007 01:45 AM

Tool for rotoscoping
Try new free tool for rotoscoping named "Claxa". It can output Bezier masks but can also work on pixel level to provide really live contour almost automatically. http://patchmaker.net/Claxa/

Emre Safak October 23rd, 2007 07:47 AM

Very clever, Alexander. It looks like you are going to give mocha a run for its money. When do you plan on releasing an AE plug-in?

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