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jonathanw48420918
jonathanw48420918
Participant
August 11, 2017
Answered

Motion tracking text onto a shirt

  • August 11, 2017
  • 2 replies
  • 3083 views

HI Guys!

I am trying to take a video that I shot of a model wearing a blank shirt (I added blue tracking markers) and be able to add text and non-moving graphics to the shirt but make it look as if it was always on there.

I want to do this to create short video advertisements for my company.  My trouble comes when there is some kind of movement in front of the text, I.e a hand moving of hair falling in front, or her rotating, I want to be able to have it look natural And move with the flow of the shirt. And to also be able to remove the markers.

if you guys would be able to help me with that I would be extremely grateful- or point me in the direction of a video tutorial - that would be wonderful.

There re is a video done by an Israeli guy if two people waking (one green and one white shirt) which shows how to get content on a shirt but it is very simple video of them just walking forward with no obstructions or position markers.

Thanks so much!

    This topic has been closed for replies.
    Correct answer Rick Gerard

    You separate the thing that are in front of the shirt by rotoscope. This involves duplicating the footage and some masking.

    The most efficient technique for tracking depends on the shot. Most of the time Mocha will be your best tool and tracking markers are usually not necessary. It all depends on the shot.

    Show us the shot and I'll try and point you to the most efficient solution.

    2 replies

    jonathanw48420918
    jonathanw48420918Author
    Participant
    August 14, 2017

    Thanks so much for writing back (and so quickly at that )

    Could you please post the image with the corner tracking?

    How would you do the corner pin (in the one corner and the other in the other corner)

    I have no problem reshooting as that was just a sample demo of some movement to see if I could even do something like this.

    How would you accomplish a person walking from the side and then turning to face the camera? would that even be possible?

    One thought... would it be better to already have something on the shirt--text and or graphic--- and then be able to track that and replace it (using the same technique for removing the tape would be) with the new/different text/graphic?

    Thanks!!!

    R
    Community Expert
    Rick GerardCommunity Expert
    Community Expert
    August 14, 2017

    Here's the shot tracked in Mocha:

    Notice that perspective is checked, that the spline includes the areas of detail that are approximately on the same plane and I have imported your graphic to add to the surface. This track worked pretty well but as you can see by the layer name this was my fifth attempt to get a good track. Because you have a curvy actor it becomes necessary to track at least two planes to get a good composite. This will take a lot of work.

    Having someone walk across frame and then turn to the front requires that the plane you are trying to track is fairly flat, that you see most if not all of the surface in the shot - which eliminates a profile shot that obscures all of the back edge of the plane. It's all a matter of careful blocking.

    Adding a graphic is much easier than replacing one because you don't have to generate a clean surface for the new graphic. Just blend modes can simulate the graphic distorting on folds in the fabric.

    Another option is to motion stabilize your shot so the shirt does not move in the frame then add your graphic. This technique involves a TV screen but it would work just as well for a t-shirt given the right blocking.

    I would practice on a few shots and experiment with Mocha's workflow so you can learn how to block the shot so the composite will work well. If you have to have the actor move in profile and then turn toward the camera it might be better to put a cut in the shot and shoot from two angles or do two separate tracks and combine the composites using multiple layers. This will give you only a few frames that need to be adjusted by hand to cover up the transition from profile to head on.

    R
    Community Expert
    Rick GerardCommunity ExpertCorrect answer
    Community Expert
    August 11, 2017

    You separate the thing that are in front of the shirt by rotoscope. This involves duplicating the footage and some masking.

    The most efficient technique for tracking depends on the shot. Most of the time Mocha will be your best tool and tracking markers are usually not necessary. It all depends on the shot.

    Show us the shot and I'll try and point you to the most efficient solution.

    jonathanw48420918
    jonathanw48420918Author
    Participant
    August 13, 2017

    Hi there,

    I appreciate the super quick answer. That's exactly what I needed to hear.

    And I have a very new question as well. On the shirts I put blue pieces of tape to help with motion tracking. However when I go into mocha and I use the x-spline tool  and I turn on perspective because the person is moving from side to side the tracking is never accurate. And when I don't understand is that the movements not very much but the tracking system keeps drifting all the time. Now I might be doing this in correctly but I figured that they should be pretty accurate for at least this.

    Do I set the tracking a little differently? Do I do a box around the whole person first and then a new layer around the marker? Do I do a layer around each marker? Or do I do a new layer and include all the markers in one? I figured that there should be a pretty accurate tracking system because you have a Contrasting marker to follow.

    Thanks so much again!

    R
    Community Expert
    Rick GerardCommunity Expert
    Community Expert
    August 13, 2017

    The best place to learn to use Mocha is here: Online Video Tutorials « Imagineer Systems

    Don't rely on amateur Mocha tutorials on YouTube. There's a lot of inefficient tutorials out there that don't really teach you how mocha's corner pin tracking works. It is important to include a little extra area around the plane you are excluding and depending on the behavior of the objects the move in front of the plane, the arms, you may need to exclude them. The best way of tracking your shot depends entirely on your shot. Sticking blue pieces of tape on the front of a t-shirt probably isn't helping you much, but again, this depends entirely on how you did it. You may want to draw a spline around the first piece of tape and then add splines to the next 3. I can't tell if that would be the best solution without seeing the shot.

    Follow the link above, follow the Browse our extensive video section​ link and then search for Shirt and you'll find some example footage and a tutorial that should help you. The tutorial is pretty darn good.

    If you are still having problems post your shot and I'll make my recommendations. It takes a while to learn how to set up VFX shots so they are easy to do in post. You'll get better at it.

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