Constraint to F-curve

I bought an add-on called re-face from the blender market. It is DIY facial mocap tool. It requires facial tracking data.

I tracked facial deformation. The steps I went through is add a set of markers on my face, then tracked those. Then I hit the "Link Empty to Track". That creates the empties in the 3D view and they follow my facial deformation. Each empty has a follow track constraint, following the specific track. But now I want to take the transformation and convert them into an f-curve. Under the constraint for the track I press "Constraint to F-curve" but that doesn't do anything. No keyframes are created. I'm using Blender 2.79. Do you have any ideas why that would be happening. Thanks in advance.

  • Jonathan Lampel replied

    Hey Amir, that looks like a really cool addon! From looking at your description I'm not sure what you're missing. I haven't used it yet, but I know the .zip file from the market includes full documentation. Is the answer in there? If not, and if the addon is not working as expected, you can contact the creator from your Blender Market inbox: https://blendermarket.com/inbox

  • amirshehata replied

    Hey Johnathan,

    The issue is not the plugin itself. It's the behavior that I'm seeing from blender:

    1. Create a tracker object in the video clip editor

    2. Add trackers

    3. Track the footage

    4. link to empty

    After step 4, I now have a set of empties, each one has a follow track constraint pointing to the respective tracker. However, when I try to do "constraint to f-curve" to make the empties independent of the camera. That doesn't work. No key frames are created.

    If I copy those tracks to the "Camera" tracker object, then "constraint to f-curve" works. 

    Is that expected behavior? or is there an extra step I'm missing when working with something other than the default "camera" tracker object.