Steps for tracking/ insert module with non square screen

What would the recommended steps be for tracking and using the insert module for a screen like an iPad or iPhone where the screen has rounded edges?

If you use the tracking layer for the insert (like the online tutorials do) the surface is square so you need to create a mask with rounded edges. You can create a mask and link it to the track, but it gets tricky if there is an occlusion such as a hand. Then you can create another mask for the hand, but Mocha Pro can’t handle the two different masks. In theory it should be able to handle a mask for the screen and a mask for the hand, both doing opposite things, but in practice it never works (I have tried every combination of blend modes and inverted masks - it just doesn’t work).

I’ve found two work arounds, but wonder if there is something better.

  1. use different layers in After Effects, one for the screen mask, one for the hand etc. but then any change has to happen in multiple places.

  2. Track the surface in Mocha Pro, duplicate it and change the mask entirely from the tracking mask to the screen mask.

A tutorial for something like this would be great. Especially if it had real world problems like a hand covering up one of the corners and part of the screen going off screen.



There is no right or wrong way of doing this. My personal preference would be to assemble the comp inside After Effects using different layers, just like you described, as it gives me more versatility in work.

But if you want to do all of that in Mocha - not a problem!

Here’s a simple project that contains 3 shapes.

  • The one is called “Screen track” is used exactly for that - that’s the base track.
  • Second layer ( the green one), is Screen Mask. It’s linked to the Screen Track, and i also use it for insert import.
  • The upper one is for finger. There’s no obvious occlusions on this clip, so i draw the yellow shape slightly bigger, just for the demonstration purposes

I selected Screen Mask layer, then inside Insert module turned on the checkbox “Use All Layers” for the mask, and that did the job!


Thank you. That’s helpful.

I’d still like some clarification on setting the surface. It seems like you have to set the surface on the Screen Track layer to make sure the track is good. But you also need to set the surface on the Screen Mask layer for the insert. In the method you describe it sounds like you’d have to set the surface layer twice - and if it’s a difficult track where you have to use adjust track you’d only want to have to set it once.

What would you advise?

(if you could copy and paste the surface that would help, but I don’t think you can)

In this scenario there’s only one Surface layer that needs ‘Adjusting’,
The Surface set up for the track layer is as you say to check it’s good, (with the pink Planer grid if you want), once the tracking is done it can be turned off for that track, (Adjustment to the Surface on the tracking layer would be pointless as it doesn’t affect the tracking data ).
The Surface for the Insert should follow correctly if the insert layer is linked to the track layer, it’s this Surface that has the insert you would do any Adjustment to, Track Adjustment is just like a final tweak of the Surface/Insert.
Each layer masks the one below, you can set it to ADD, Subtract & Transparent, these layers blend modes can also be Inverted, & in the Insert tab there’s additional choices for layer masking as Elizabeth showed,
All of these will affect how the final look is depending on the setting & layer order of each, but it’s not easy to describe in text this order of masking, so if as you’ve mentioned you’re also adding in AE masks the possible combinations are numerous, watch every vid available & do lots of experimentation,
Have a look at this vid, it shows a mask over finger, insert etc…

Yes. I know this video. It shows a method for Mocha AE. I am trying to figure out a more specific issue in Mocha Pro.

I think you may have answered a relevant question that I was unclear on though. Can you confirm that you are supposed to use Adjust Track on the Screen Mask layer even though it is linked to the track on the Screen Track layer? I had thought that you were supposed to get the surface tracking perfect on the Screen Track layer and just link to that. I didn’t realize you should use Adjust Track on the Screen Mask layer that has no tracking data of its own.


A track layer tracks using the information gathered from within the spline, the blue surface layer (with the pink Planer grid) is used as a visual guide to see how the tracking is going, to use Adjust track on this would be pointless & result in give false info about the tracking,
A mask layer uses the spline to mask an area, the blue surface isn’t relevant to this, so again to use Adjust track on this would be pointless.
An insert layer transfers tracking information from its spline to its blue surface layer, if the blue surface/insert doesn’t go exactly where you want you can tweak it using Adjust Track but this tweaking doesn’t change the splines orig tracking data,

I might be wrong with this definition but I think you’re thinking that using Adjust Track in some way helps get a better track, it doesn’t it’s just an extra final tweak to get your insert in the correct place.

No, you do not have to use Adjust Track.
In the setup that I’ve showed you above, I use Screen Mask’s surface to align the insert.
You can use Screen Track surface to check how good your track is, but Screen Mask would follow that motion anyway, so that’s not necessary to have two perfectly aligned surfaces.

However, when you do have a hard track, and you need to use AdjustTrack, i would follow the next workflow:

  • Create layer that you would use for the track, and Alight your surface.
  • Use Adjust Track on this layer as you normally would.
  • Once your track in done, duplicate this layer. The surface would be in exact same place as on original layer.
  • Now you can draw a new shape on this layer for a mask, and delete the old one that you’ve use for track.
  • You can leave everything as is, OR, if you’d want to continue adjusting the original track layer, you can use Link to Track, and turn on the “Adjusted” checkbox.

    The surface on the copied layer should perfectly follow the surface on the track layer.

Hope that helps!