8 Replies Latest reply on Feb 17, 2010 12:40 PM by Lost In My Mind


    Lost In My Mind Level 1

      Here is a simple (and yes, dumb one). Tried to green screen someone jumping, but the only thing green was me when I saw the footage!  :O  It's only 1 second long, so I thought I would do it manually. Frame one, I create a mask around the subject and everything else disappears (perfect). When I move down one frame the subject has moved, but the previous mask background stay in the picture :/  What's up with that? And yes F1, Chris and Trish, etc. Thanks. Cin

        • 1. Re: Rotoscoping
          Todd_Kopriva Level 8

          Your question isn't clear to me. Can you tell us exactly what you're doing?


          You said that you drew a mask on the first frame. OK. Then you moved to the next frame. Then what? Did you animate the mask path and draw a new path for the mask or modify the existing path?


          There are tips for rotoscoping in the "Rotoscoping introduction and resources" section, as well as links to several free tutorials and articles and movies that show how to rotoscope in After Effects. Please check out some of those tutorials and report back with specific questions, with details about exactly what you're doing and exactly what the results are.

          • 2. Re: Rotoscoping
            Lost In My Mind Level 1

            Thanks Todd, I know your standard answer is RTFM, but you need to understand I DO. I am a member of Lynda.com and spend several hours there a day, as well as many other spots that you and other members have recommended. Sorry I'm not the sharpest knife in the drawer, but it isn't because I don't try....... Anyway, I'll struggle for a few more days and am sure I will figure it out eventually. Cin

            • 3. Re: Rotoscoping
              Todd_Kopriva Level 8

              Actually, my answer in this case was not RTFM as much as "watch the videos linked to from TFM". And then tell us exactly what you're having trouble with. It's very hard to help when the description of the problem is vague.

              • 4. Re: Rotoscoping
                Lost In My Mind Level 1

                If I would have known the description was vague, do you really think I would have posted it??? If someone asks a vague question on one of my boards, I hardly think that was their intention. I usually give them the benefit of the doubt, and ask for further details and descriptions. Cin

                • 5. Re: Rotoscoping
                  TimeRemapper Level 4

                  ...and ask for further details and descriptions...


                  Todd did ask you some questions to determine more information about the nature of your problem...


                  Then what? Did you animate the mask path and draw a new path for the mask or modify the existing path?


                  From your initial description, it seems as if you're not animating the mask path.

                  Rotoscoping is the process of animating a matte over time. You can't just set the initial mask, and expect it to automagically follow whatever it is you're trying to extract from the background.


                  If I would have known the description was vague, do you really think I would have posted it???

                  I don't mean to insult, but please don't be defensive. In the grand scheme of things, your description was a little vague.

                  Admittedly, it's hard to phrase questions precisely and succinctly until one has a complete knowledge of the relevant vocabulary and terms.

                  That is all part of the learning process.

                  Todd (and many others) work hard to make the online help files and online community forums a robust source of knowledge for all users.

                  Let's see if we can get down to the precise nature of your problem, and get you on your way to solving your issue.


                  You also mention the footage was difficult to key.

                  Can you post a sample? Sometimes using different types of keyers may provide unexpectedly good results.

                  Even combining multiple layers and effects can be effective at pulling keys from footage that looks as if it would be very difficult from which to obtain a clean signal.

                  • 6. Re: Rotoscoping
                    Lost In My Mind Level 1

                    Thank you TR for your advice and help. It would seem that I am drawing separate masks for each frame, instead of working with the original throughout. I get sort of a 'strobe motion' effect. I will keep working on it and see what I can do. As for the green screen, it was well done, but the subject jumped out of it causing this problem. As for Todd and the rest of the members, and their willingness to help.......that is beyond reproach. Thanks again. Cin

                    • 7. Re: Rotoscoping
                      TimeRemapper Level 4

                      No problem.

                      Rather than drawing a new mask path on every frame (consequently increasing the number of masks that you have on your layer), you should be able to get good results from changing the shape (and keyframing the change) on your original, solitary mask on every frame of motion.


                      You should be able to do the whole thing with one mask shape and multiple keyframes.

                      However, many people find it easier to create a few initial masks:

                      • One for the head
                      • One for the torso/pelvis
                      • One for the left arm
                      • One for the right arm
                      • One for the left leg
                      • One for the right leg


                      While the initial setup creates 6 masks instead of just one, those should be the only masks that you need to pull a nice roto-job.

                      The multiple masks allow the user more control over setting keyframes for parts of the body that move more/less than other parts.

                      The strobing that you're mentioning is not uncommon when the shapes get clipped by the edge of the mask path.

                      Increasing the feather a little may help in this situation.

                      If you have whispy hair that needs to be rotoscoped, this will be your greatest challenge. Long hair is always tough.


                      A good technique is to set your initial keyframes, go about halfway through your second-long footage, and adjust/keyframe your mask(s).

                      Then, go back in between your two keyframes, and add additional ones as needed.

                      You very well may not need a keyframe on every frame for all body parts. This will help ease the strobing effect as well.

                      Fewer keyframes = simpler motion = less stutter/jitter

                      • 8. Re: Rotoscoping
                        Lost In My Mind Level 1

                        Thank you TR for sharing your time and knowledge, both are greatly appreciated.  I learned a lot of good stuff from you that I hadn't found anywhere else. Cin