VFX – Planar Tracking with Mocha

Recap – 1 Point Track

As a recap on the tracking we already knew, Peter ran through a 1 point example before moving onto Mocha and it’s planar tracking. So this is just a quick bullet point reminder.

  • Import chimney and smoke footage into the new composition, matching the video settings.
  • Add two nulls, tracker and control.
  • On chimey clip, tracker panel (right hand side) > track motion
  • Set tracker box size, align to chimney
  • Analyse forward

capture1

  • Tracker box/cross stays on screen as the chimney vanishes. To remedy this, pick a new reference point nearby the first, that’s still on screen at the last frame the chimney is tracked (used the corner of the upstairs window).
  • Alt-click to move the tracker box to the new reference point and analyse forward again.
  • Edit Target > Tracker Null > X & Y Apply Dimension, Tracking Information is now assigned to the tracker null.

capture4

  • New Black Solid > Above particle smoke layer

capture5

  • Track Matte on Solid > Luma Matte
  • Using Pan Behind Tool > Move pivot point of black solid to the bottom of the smoke
  • Parent Black Solid 1 and the smoke effect video to Tracker Null

capture7

  • Resize smoke, place it where you want it here is the result.

chimney_smoke

The main difference with this exercise and the first one we did, is that the tracking point is lost partway through the footage. This was fixed by adding a second reference point part way through the footage as mentioned above.

Planar Tracking

After it being teased before Christmas we finally get to have a look at Mocha.

 

First in After Effects, import your footage into a new composition and bring it onto the timeline. Highlight the layer and then go to Animation > Track in Mocha AE. This opens up a lightweight version of Mocha that comes bundled with AE.

Browsing through the footage we needed to find a good clean frame to setup an area for planar tracking. To do this we used the X-Pen tool to draw out a section of the wall and right clicked to close the loop. This red loop will be our tracking information.

mocha-planar-shape

Now we needed to define the area our image would be projected onto. This requires the use of the Show Planar Surface tool, as above this allows you to draw a box but with a blue outline. Once this is set, hit the track backwards button, when finished return to a frame before you started the track and then track forwards.

Now press ‘Export Tracking Data’ and copy the provided info to the clipboard. Returning to After Effects we created a new black solid, highlighted the layer and pasted the tracking information onto it. This immediately masks out the solid to the shape of the blue outline we created in Mocha.

Not many more steps now. Pre-compose the black solid, open up the pre-comp, add the graphic we wanted to display on top of the black solid layer, resize to fit composition and return to the original composition. Change the blending mode, opacity, add a motion blur effect and voila!

tunnel_dragon2

For simple tracks like this, Mocha is FAST to use and the end results look great.

To cement the process into us Peter wanted us to run through another planar track on another piece of footage. The footage showed a passing train and the aim was to add the words planar tracking along the side of a carriage using the same steps as above. Here is that exercise completed.

train_tracking

This kind of work is SO easy with Mocha, I could repeat these results in about ten minutes. Such an amazing addition to After Effects!

 

 

 

 

 

 

 

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