3D Model Motion Tracking Without Mocap Suit

Hi, i recently got some 3D models of some robots and wanted to have them copy my movements but i don't have a MOCAP Suit and the 3d stuff is kinda new to me i don't want to have to animate it by myself. instead i was wondering if i could use a Green screen suit and track it then get some clean plates and replace the green screen suit with my model?. 

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  • Hi, i recently got some 3D models of some robots and wanted to have them copy my movements but i don't have a MOCAP Suit and the 3d stuff is kinda new to me i don't want to have to animate it by myself. instead i was wondering if i could use a Green screen suit and track it then get some clean plates and replace the green screen suit with my model?.

  • Triem23Triem23 Moderator

    Not really. There are suitless options (like the old Xbox Kinect), but those don't work that well.

    More importantly, mocap data requires setting up a skeleton hierarchy so the computer knows which markers connect to which other markers to keep everything in synch. Standard point tracking will only give you a 2D position, rotation and scale. Oh, you could connect, say, a two-point track at elbow/wrist and assign a forearm to that point, but without the knowledge of connection to a shoulder, and with 2D - not 3D- data, it's not going to work. 

    Your options are as follows.

    1. You can buy a motion capture solution. Even using a "suitless" option will cost a lot of money. You'll be spending hundreds on the software and hundreds - if not thousands - on the required camera array. 

    2: Mixamo. See video.

    https://youtu.be/a7DrlUMxQcg

    3: Learn to animate. 

  • Triem23 Thanks so much for the reply' Mixamo seems to be really cool i did not know about glad you shared it with me. quick question/s 1.can you import your own 3d models like ones from Turbosquid.  2.would have or know any good tutorial videos on animating 3D models inside of Hitfilm.

  • Triem23Triem23 Moderator

    Mixamo allows you to upload models, yes. 

    Animation in Hitfilm... For a humanform robot my advice is to learn how to animate in Blender and export animation from Blender to Hitfilm. 

    In 3D animation there's a feature called "Inverse Kinematics" (IK) which relates to the skeleton. Basically it's identifying a skeleton/joint hierarchy, so, if I grab a wrist and move it the software goes up the skeleton and moves the elbow, then shoulder, etc if the new position of the wrist requires it. 

    And Hitfilm doesn't do IK. You have to animate from the shoulder down to move a wrist. It's a massive pain to match up, say, feet on the ground while walking. 

    I tag in @ZachAlan_Productions. A few years ago Zach wanted to animate an At-At. I recommend Blender, but talked him through the process in Hitfilm. He did the walk cycle, and it looked great, but he'll tell you it was a lot of fiddling about, and that it's easier to animate in a dedicated 3D program. 

    Otherwise I tag in @spydurhank and @NxVisualStudio. Frank (spydurhank) is the leading expert in Blender/Hitfilm workflow and @NxVisualStudio works in 3DS Max, but also animates and composites in Hitfilm. Both are more knowledgeable on this topic than I am (and I'm not bragging when I call myself one of the top 1% of Hitfilm's userbase in expertise). Both of them should be able to give advice on exporting the FBX animation you'd need import to Hitfilm. 

    Mixamo exports FBX as well. Si, learning how to export FBX animation is what you want for comping in Hitfilm.

    This video discusses how to export Alembic (ABC) animation from Blender for Hitfilm. FBX is a stronger format than ABC, but this should show you a similar process as what you'll do for FBX. 

    @tddavis @Stargazer54 @GrayMotion can you guys recommend any good starting tutorials on rigging, IK an character animation?

    For 3D animation in Hitfilm, it does well for more mechanical objects (cars, copters, planes, certain types of robots)

    I'll recommend my own tutorials here (Part 1 of this three parter keeps getting deleted by YouTube and I'm not doing a fourth edit). These two get into rigging for complex 2D animation and an overview of rigging a 3D model (a Dalek)

    https://youtu.be/NHXbO6wuBS0

    https://youtu.be/EXA804S2Dwo

    These should cover the same stuff as my deleted tutorial. 

    https://youtu.be/6ZOsK7q0QD0

    https://youtu.be/iZCc1Rva8jk

    https://youtu.be/TE1Z7cIxg1g

     

  • @filmingdude4567 I don't think this would work. In principle, tracking works by examining a certain area and the pixels around it to try and track where the area has moved to. If a large region is identical in color/pattern to the tracked area it will cause a lot of issues and need a lot of modification by hand since the track will easily get confused. This is why you always see dots or other simple points on the faces/bodies of actors when they are tracking. Furthermore, by tracking 2D footage you are only estimating a 3D position based on what can be seen in the shot, whereas a motion capture suit understands the movements in 3D space.

    Additionally, motion capture suits typically have at least ~15 sensors for tracking, which are not always visible to the camera (ie, the back and spine) and would be a lot harder to track by hand if the actor was facing forwards.

    I personally believe you will have a harder time manually tracking all of the relevant points, but that does not mean it is impossible. I would suggest you do not use a completely solid colored suit however, perhaps look at images such as the one below and consider how the targets allow for easier tracking over a solid green suit.

     Image result for film tracking suit

    Disclaimer: I am no expert, but I do have experience using basic motion capture suits. Someone else may be able to provide a much more informative insight into this workflow.

  • Triem23Triem23 Moderator

    @TheBenNorris of course a suit is a single expensive thing, while suitless usually requires three if not six cameras... 

  • @Triem23 ah, I see you merged the threads, thanks!

  • edited November 1

    The OP might try this :

    https://getrad.co - RADiCAL

    It's not free but there is a free trail.

    I have not used it yet but I've seen GC Geek's example here:

    https://www.youtube.com/watch?v=fwc9vTCLYCc:

  • edited November 2

    @filmingdude4567 ; @Triem23 ; This is a pretty quick tutorial for basic armature creation, and informative, but it is for more intensive by-hand animation.

    https://youtu.be/SBYb1YmaOMY

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