04b Tracking Tips - Track Mattes [Mocha Essentials]

When our tracked object gets covered, either partially or completely, all can seem lost. This exercise shows how to use track mattes to only track in the areas you want and ignore the rest.
This video goes beyond simple track matte techniques, and encourages you to think about why a track may be failing, even if it looks like it should work. You will use and improve on the tracking skills you have built up to this point, and achieve the perfect result.
By the end, you will know how to properly use track mattes in Mocha and understand how to use co-planar shapes to create a rock solid track.
Chapter List
00:00 Start
00:45 Setting up the initial track and failing
05:33 Adding a track matte
09:52 Diagnosing and fixing problem tracks
Watch the full series free! bit.ly/31JZ2OG
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#borisfx #mocha #motiontracking

[@terr20114]

The information you guys have on your channel is phenomenal. Wish every company did this. Wouldn't need to be going to 3rd parties to learn some things.

[@borisfxlearn]

Thanks. There's a lot of effort that goes into these. I'm glad you're liking them.

[@facu_eze_peralta]

I just love it! This is awesome!

[@kratosjordan8438]

Thank you so much, I bought this tutorial, but still like to watch on youtube to give you guys a thumbs up.

[@borisfxlearn]

Thanks so much. I'm glad you're working your way through the course and becoming a Mocha Pro pro!

[@rowanwhile]

The fact that you have these tutorials and that they come across as so down to earth and understandable... in chunks... no "blinded by science" moments.. Has encouraged me to buy Mocha Pro.. Thank you so much for creating these.

[@borisfxlearn]

I appreciate that. Thank you for wanting to learn Mocha. I will let Ben and Mary know you're enjoying the series too.

[@CaseyDrogin]

Been using Mocha for years and already learning so much! Hands down one of the best courses out there. Thank you for the upload!

[@borisfxlearn]

Thanks Casey. It means a lot to hear that.

[@eladet11]

I'm in the middle of your course and just wanted to tell you that it's really great!

[@borisfxlearn]

Glad you are enjoying it! See you in the comments at the end :D

[@tief1975]

I am a bit confused about how to identify those 2 parts of the wall as being on the same plane. could you expand on this? cheers

[@borisfxlearn]

Sure. Simply put, a coplanar area shares the same movement relative to the viewer. That wall has the same relative planar movement towards the camera regardless of where you track it. Of course, it's not quite as simple as that but you can learn more in this video : kzbin.info/www/bejne/h5ibmoirg9OCnq8

[@isaacsvensson4305]

Is the default behavior of two tracks to subtract the area of the top "track matte" from the "wall track"? Or do I have to tell "wall track" to subtract "track matte"?

[@borisfxlearn]

The default behavior of any tracks above the one(s) you are tracking is to subtract the area from tracking. You don't have to set anything special. The "Subtract" setting in Layer Properties is just to change how the masks combine when rendered.

[@kazerani1364]

Hi there, thanks for your helpful videos. In my video, there is a computer in the background with no green screen, and I want to replace the screen. Still, the most difficult part where I struggle is when an object in the middle of the shot blocks the monitor screen for a few seconds while the camera is panning from left to right. I have been following your videos, but it doesn't work in my shot, and I am struggling. What is the best video to watch it?

[@borisfxlearn]

Have you tried the Extrapolate Track option? Track to the last good frame, then turn your tracking mode to Extrapolate (you will have to be in the Classic workspace to see this option). Track forwards a few frames and it will keep moving with the same velocity as the previous frames. If your camera movement is smooth, then this will give you a good base to work with. When the object stops blocking the shot, turn the Track Motion mode back to Large Motion and track as normal. A couple of things to note. If your camera movement isn't completely linear then this won't work 100%. But that's OK. When the object is clear, position your tracking spline back to the computer and track forwards. Your "Surface", the actual tracking data, won't be matching perfectly. But that's when you go to AdjustTrack and finish the job. Start on the last good frame, make another keyframe on the other side when you can see the object again, and then tweak from there. You should only need a few keyframes. Here's some good resources : How Mocha thinks : kzbin.info/www/bejne/h5ibmoirg9OCnq8 Basic AdjustTrack : kzbin.info/www/bejne/fIqWiIqhq5aZerM And if you're still having problems, please join us on the forums or Discord channel to get some further ideas : forum.borisfx.com/ www.borisfxdiscord.com/

[@angulurivamshi5058]

Hello there. Appreciate your efforts. Thank you very much. I'm getting a problem when tracking with multiple shapes. When the shape is going out of frame. The track is stopping there and getting a popup as "The terminated permanently due one or more track were not tracked properly. Try to increase the minimum percentage of pixel used". I'm getting the same problem after increasing the shape. Hoping to get some help.

[@borisfxlearn]

Mocha is almost magic, but not quite. If the shape goes too far offscreen then it's tricky to keep the track going. As Mocha is a planar tracker, if you position the shape over a co-planar area you can continue tracking with that. Mocha only needs this to be coplanar. This concept is shown quite nicely with Unlink tracking : kzbin.info/www/bejne/fInahImggZhqbLc It might be easier to help out if you join us on the Forums : forum.borisfx.com/

[@rahuldeshpande3516]

Hey man! Question. So to solve the problem with shapes screwing up, instead of extending the left shape and moving it up, I drew another shape on the right hand side of the video. And then when I tracked, it worked! I believe this is also an acceptable solution yeah? Cos the way I understood it, the Track Matte of the walking person was cutting out the shapes and therefore the areas weren't enough for Mocha to search and track. Therefore, defining a new shape for the same layer would give more area for Mocha to search for, and would hence make the tracking successful. Thoughts?

[@borisfxlearn]

Yes, so long as the areas are co-planar, that is they sit on the same plane and share the same relationship to the camera, adding another shape to the layer is a great way to continue an otherwise impossible track. Your comment is exactly correct.

[@rahuldeshpande3516]

@@borisfxlearn thank you!

[@ronydey2696]

Nice sir how to offset track while rotation and skew of that camera shot?? Hi sir myself Rony an VFX student from India

[@NidalDumi]

hello, i have the same problem, can i ask a question. how can i make the logo to offset when the person move in front of the logo, beacouse as u in this tutorial the logo stay in front of the person?

[@borisfxlearn]

You can try to track something else that is co-planar (has the same relative movement to the camera). Or you can skip the troublesome frames, and continue tracking when the area is clear again. If you do that, use AdjustTrack on the last good frame of part 1 of the track, and the first good frame on part 2 of the track. That should get you a consistent result that you can use.

[@AFuller2020]

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