5 Replies Latest reply on Oct 15, 2016 1:57 AM by Mylenium

    questions about rotobrushing

    PremiereNoobSigh Level 1

      is there any way when rodobrushing to prevent AE from making the same mistake over and over again every frame? as in lets say im rodoscoping a face and AE accidently thinks that a little bit of his white collar shirt is part of the face, ill erase that white collar part and then move on to the next frame but the next frame catches the white collar part again....i thought the change i made would be recalculated by AE when AE automates the next frame but apparently not, or im doing it wrong

       

      is there a way to disallow certain colors from entering the rodoscope or have the rodo take into account what ive changed when estimating the next frame? is there a difference between hitting space bar or to hit 1 or 2 to rodo?

        • 1. Re: questions about rotobrushing
          Roei Tzoref Adobe Community Professional
          is there a way to disallow certain colors from entering the rodoscope or have the rodo take into account what ive changed when estimating the next frame?

          Rotobrush does this estimation automatically based on different techniques (tracking, optical flow and more) and also of course on what information you provide with your first base frame and corrective strokes, and carefully setting up the parameters (search radius, . the rotobrush workflow is not that short and requires patiantly following along and not missing a step or you will find yourself wasting too much time and with poor results.

           

          please read through this carefully: Roto Brush and Refine Matte in After Effects

          Roto Brush and Refine Matte in After Effects

           

          notice step 8

          if the segmentation boundary that After Effects calculates for the current frame is not where you want it to be, then you can make corrective strokes to teach After Effects what is foreground and what is background. Draw foreground strokes and background strokes as needed to correct the segmentation. Corrective strokes propagate in one direction, away from the base frame.

          note: You can also modify properties in the Propagation property group to affect how After Effects propagates the segmentation information from previous frames to the current frame. (See Roto Brush effect and Refine Matte effect reference.)

          notice the propagation category

           

          right after you set your base frame, go one frame forward or backward (depends where you want to advance) and check your search region and experiment in different edge detection options. once you find the right that suits you best, it's corrective strokes from now on.

           

          is there a difference between hitting space bar or to hit 1 or 2 to rodo?

          space bar can only play what your rotobrush cached into memory.

          • 2. Re: questions about rotobrushing
            PremiereNoobSigh Level 1

            hi thank you for the detailed response

             

            would u say its better to use 1 and 2 or space bar or another method i dont know of in terms of allowing rodoscope to autocorrect and reanalyze past/future frames after ive made a correction

            • 3. Re: questions about rotobrushing
              Dave LaRonde Level 6

              Actually, I'd step though frame-by-frame.  You can correct mistakes as you go.  In the long run, it saves time.

              • 4. Re: questions about rotobrushing
                Roei Tzoref Adobe Community Professional
                would u say its better to use 1 and 2 or space bar or another method i dont know of in terms of allowing rodoscope to autocorrect and reanalyze past/future frames after ive made a correction

                what do you mean by 1 and 2? you go one frame, if there's a need for correction you do it. that's how you do it. space bar won't do anything but playback what's already cached.

                • 5. Re: questions about rotobrushing
                  Mylenium Most Valuable Participant

                  would u say its better to use 1 and 2 or space bar or another method i dont know of in terms of allowing rodoscope to autocorrect and reanalyze past/future frames after ive made a correction

                  Until you freeze the RB, the propagation is always dynamic in both directions. You modulate the underlying motion field and feature detection, you don't paint a matte per se. The brush is just a tool to mark out the areas for the underlying algorithms, not the masking itself. How the propagation is initiated therefore is irrelevant. It will always happen if data is missing, changed or updated.

                   

                  Mylenium