Your First Day using Mocha in After Effects on Pluralsight
For motion tracking, Jonny (Iglu Media) suggested looking into Mocha in After Effects as this would be useful to their own projects. This is my first time looking at motion tracking and it seems quite straight forward. This tutorial involves using Mocha to draw points around what you want to track, tracking with Mocha ‘track’ button and then adjusting the track using the ‘adjust track’ tab and nudging the points back into position if they move off track.
From what I understand (from other tutorials also), Mocha uses a planar surface (made of corner pins) to track with while the tracker in After Effects tracks using a point, or two if rotation is involved.
These are my notes from the tutorial:
02 Tools and Interface: Go to animate>track in mocha AE. Use the pen-like tools to create masks and selections. The ‘B’ pen creates a Bezier selection like the pen tool. The ‘x’ creates a shape selection which you can create a mask from. On your timeline, figure out where you want to start. Figure out where you want to end and create an endpoint with the bracket-like button. Track forwards with the ‘track forward’ button. Then create an in-point and track backwards towards it. Create a planar surface and align it in perspective. Use the planar grid to help.
03 Tracking Planar Surfaces. Add more planar selections as needed to aid the track. To correct a grid which is skewing open up your parameters menu.
04: You can toggle the overlays and grids on and off so as to see if your composited logo/object is behaving okay.
05 Exporting data to after effects: Open Mocha through AFX and open an existing project with the folder icon. Make sure your layer is selected in the layers tab and then open the parameters tab through ‘view’ on toolbar. Choose ‘export tracking data’ and ‘AFx corner pin’ middle option. Copy to clipboard. Go back to AFX and select the layer that you want to add tracking data to and paste. If you need to adjust a keyframe in AFx, make sure to use the slider value as this will affect the entire timeline. Adjust blending mode and blur etc. as needed.
06 Tracking Problematic surfaces: Use the x pen to add a rectangle area. For the tv screen in the tutorial, use the x+ pen to remove the screen and only track the area around it. Track forward. Use the planar surface (blue) to see how the track moves. Use the pick tool to move the surface into perspective. Now we adjust the track. Go back to the beginning. Hit ‘adjust track’ to set keyframes in place for our adjustment. Scrub through the timeline and use the nudge keys to move the plane back into place.
06 Overcoming obstacles in your tracking. Lock the layer with your previous complete tracking data and turn off further tracking. Draw around the sign you want to replace. Remember, right-click to complete tool. Track the bus forward and then backwards. You’ll see problems as the bus goes behind the pole. We need to remove the pole’s influence. Lock the bus layer. Use x pen to select pole. Track the pole, then under layer properties make the blend mode ‘subtract’. Lock this layer and make un-trackable again. Make bus trackable and unlock, then re-track. Now we add our tracking plane. Go to the point where the planar surface is acting great and hit ‘adjust track’ tab to add a keyframe. Scrub though to see what areas need nudged in comparison to master frame.
07 Export multiple tracks to AFx: Copy and paste as usual. If the graphic is in the wrong place, Use the anchor point sliders to move it.
08 Using mocha to create shape data and manual keying. For pole, we will use the previous tracking data. Create the shape of the pole using the b pen. Then in the layer properties, link the track to the pole tracking layer. For the car, outline it with the x pen. Choose manual track under the track tab and move the shape into place as you scrub through the timeline. Do the same for the heads.
09 Export shape data to AFx: Make sure your women, car and pole layers are visible, then under the ‘track’ tab, export shape data and ‘all visible layers’. Make a new solid layer in AFx and paste your shape data. Use this as an inverted track for ‘mask for bus’ layer.