3 Replies Latest reply on Jul 12, 2016 1:53 PM by Szalam

    Link position of a Null to a layer in the parent composition

    leneopen

      Hi everyone,

      i'm getting crazy with this problem:

      I have a character rig which is scaled down and linked to a Null tracker on a footage in a composition so that my character stay in my case on the teethbrush of a little girl.

      In that character rig, i have a Null to control the hand position, and i want this Null to match the position of another null tracker in the parent composition, that Null is tracking the nose of that girl so he can move on the teethbrush and try to touch her nose so you understand the action.

      I succeeded in another composition where the character wasnt linked to any Null or scaled using this lines that i found i dont even know where :

       

      L1 = comp("03-SceneTable Comp ").layer("Tracker.Perso Toaster");

      s = comp("03-SceneTable Comp ").layer(thisComp.name).startTime;

      L1("ADBE Transform Group")("ADBE Position").valueAtTime(time+s)

       

      Didnt worked on this case, i also tried using toWorld expressions in various ways but it never matched the position of the Null i wanted, any ideas ?

      Thanks a lot in advance

       

      n.

        • 1. Re: Link position of a Null to a layer in the parent composition
          Rick Gerard Adobe Community Professional & MVP

          This sounds like you want to use parenting. It is hard to tell because we can't see your timeline and the modified properties of the layers.

           

          If I understand things correctly:

          Parent comp:

          1. Tracked the nose of the character
          2. Applied tracking info to the null
          3. For clarity we name the null "nose track"

          Character Comp:

          1. Character rigged with nulls
          2. The important null is the one attached to the hand
          3. For clarity let us name the null "hand null"

          The problem: Attach the Hand null to the nose null but with an offset.

           

          The solution.

          1. Add a new null to the Character Comp and name it "nose tracker null"
          2. Drag the Parent comp timeline above the Character comp timeline so you can see both timelines
          3. Select the new 'most tracker null' in the timeline and press the p key to reveal the position property
          4. Select the 'nose track' null in the Parent comp and press the p key to reveal the position property
          5. Alt/Option click on the stopwatch for position for the "nose tracker null' in the Character Comp to start an expression
          6. Drag the expression pickwhip from the 'nose tracker null' in the Character Comp to the position property of the 'nose track' null in the Parent comp and release
          7. The expression should now read: comp("Parent").layer("nose track").transform.position
          8. Parent the hand null to the nose tracker null

          You should be done.

          • 2. Re: Link position of a Null to a layer in the parent composition
            leneopen Level 1

            Thanks a lot Rick, but that doesnt work unfortunately, that was my first attempt aswell of course.

             

            The "Parent comp" and the "Character comp" are different size, plus the "Character comp" is scaled to 30% and linked to a Null having tracking data,

            i have at some point to use expressions like toComp or toWorld i guess, but a simple parenting doesnt work in that case.

             

            Any other idea ?

            Thanks in advance,

            • 3. Re: Link position of a Null to a layer in the parent composition
              Szalam Adobe Community Professional & MVP

              Having your comps at different scales would make this fairly complicated. It might be faster/easier to just open up a second comp viewer so you can see your main comp and just animate the hand instead of trying to attach it to a tracking point or something.