Introduce motion to stabilized corner pin workflow

hi everybody. Mocha Ae 4.0.2

I am trying to figure out something. I have a screen replacement video that I want to composite over.

I tracked the footage in Mocha and used corner pin tracking. pasted as “invert” in Ae because I want to composite over a stabilized footage. now the screen stands still and everything else moves. good! I finished my composite… now how do I re-introduce the motion to the shot? if it was transform tracking I would precomp and collapse and use a null with the uninverted data and connect it to the precomp when the footage is full frame - but how do I invert and inverted corner pin data? :confused: what’s the exact workflow for this? a tutorial would be nice too.




o.k I got it. I just need to push the surface plane when I am copying my reversed stabilization and if the dimensions are too extreme I just place my footage underneath to compensate for missing pixels. here’s the workflow:

feel free to correct me of course.

my next question would be - how do I account for motion blur when I was actually working on a stabilized precomp and later re-introduce the motion? I can only think of setting a matte for my trimmed footage and this way I can check motion blur on for this layer…

I got the motion blur figured out… I just need to set a cropping stencil alpha for my stabilized precomp and enable motion blur for the precomp in the master comp… I need to do a tutorial about this :slight_smile:

I am glad you are all sorted!

Thank you Mary. I want to update for whoever needs this and please correct me if I am wrong.

the workflow for corner pin stabilization and re-introduce the motion I have practiced successfully is this:

  1. export the track as corner pin (with motion blur) and click invert (it does not matter where your planar surface is…)

  2. paste on a duplicate of your shot and precomp -> move all attributes and call it “stabilized”

  3. set the video as a guide layer so it won’t render later composite your shot on the stabilized comp.

  4. in mocha, find the first frame of the beginning of the track (it will have a keyframe) and set your CTI on there, push the planar grid to corners and export the corner pin (with motion blur) and paste on the stabilized precomp. set motion blur switch for the stabilized precomp and you are done.

(one quick questions: how do you find it if you lost it? does it store somewhere?)

How do you find what if you’ve lost it? Sorry, that was a little unclear.

Thank you Mary. my questions was: how do you find the first track frame you started in? it is important to set this specific frame to push planer to corner in order to reverse stabilization.

Stabilizing on the first frame of your track should not matter, but where you align your surface tool full frame should. That will be where you would like your frame to be centered and full frame and it can change depending on your preference.

Sorry for the late response, we are between the Holidays right now.


Have you checked out this method?

Sorry for the late response, we are between the Holidays right now.
Thank you Mary. will wait patiently until you will have the time of course and happy holidays :)
Stabilizing on the first frame of your track should not matter, but where you align your surface tool full frame should. That will be where you would like your frame to be centered and full frame and it can change depending on your preference.
I see now that I should push planar to the surface on the first full frame. it's usually the first frame but could be different. it does not matter where I "started" my track.


Have you checked out this method?
thank you but not using the invert function nor the corner pin. what I really need is a full workflow steps for motion stabilizing corner pin. this use is very handy for stabilizing and re-introduce the motion after the composite.


I would please also would like to get a response for what appears to be a bug described in section 2 of my previous response. and if possible an answer to section 1 too. I believe this information is very valuable although I have not seen threads about it.

O.K I know I said it before but I think I finally got it. this is what is happening:

  1. when I export as invert corner pin, the planar surface is “recorded” as a push to corners planar when I first started the track. meaning it does not really matter how I change the planar surface at this point in time, it will be as a full frame push to corners planar surface at this specific point in time. I can decide I want another frame in time to be my full frame stabilized shot if I push planar to surface at that point in time.

  2. after I paste the invert data, in Ae that point in time will be where my frame is full frame to the dimensions of the composition

  3. for some reason when I duplicate the layer, the planer surface get’s recorded this time at the first frame of the entire track. if I touch the planar surface in the first frame I started the track, it will reconnect with the information and now I can again export and in this frame it will be as a full frame push to corners.

so the workflow is this:

  1. track your shot as normal

  2. at the point in time you want the frame to be full frame fixed, push the pins to the corner. remember this frame number for later to re-introduce the motion.

  3. copy as corner pin (I will take Jps’s advice that this is better to use that as invert instead of corner pin + mb ), choose invert

  4. paste in Ae at the beginning of the layer.

  5. composite your shot, do whatever you need. at the end - precomp ->move all attributes

  6. in Mocha, find the frame where you pushed the planer to corners (it’s in the same place if you did not change it) and copy as corner pin (witn mb if you want) without checking invert

  7. paste in Ae. now you have introduced the motion.

it is better to leave just the composite inside the precomp and not the full frame footage as it will get cropped during the introducing of the motion


I think that’s it. the only thing to remember really is to make sure the planer surface is pushed to corners at the same frame when I copy the inverted corner pin, and later when I copy the corner pin. what threw me off was the fact that it get’s recorded firstly at the first frame I started the track, the fact that it does not matter how it looks as it will be pushed to corners, and the fact that if you duplicate the layer, the planar surface push to corners is at the first frame.



OK, perfect, I am glad you are all sorted! Happy Holidays!

Thank you Mary you too. hopefully an in depth tutorial on inverse corner pin using the invert feature will be released by your skilled team hands eventually. maybe I will make one myself since I think this technique is really valuable. reversible stabilization is very handy.