motion tracking
Posted: 08 September 2017 06:54 AM   [ Ignore ]  
Total Posts:  33
Joined  2012-07-26

Hi Cineversity,

My boss wants me to wrap paper around this cube like wrapping a gift, (attached sample). Can C4d’s motiontrack feature track the Cube’s position information, and I could place my wrapping animation into the motion tracking coordinates/information? I’ve seen tutorials where video is tracked, an object is placed on a street, but I need to animate the wrapping paper over the cube.

There might be shots where Cube is rotating slowly.

Can you help guide me to correct technique, direction?

Thank you!

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Sample_Cube_Cineversity_H264.mov  (File Size: 1413KB - Downloads: 16)
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Posted: 08 September 2017 10:24 AM   [ Ignore ]   [ # 1 ]  
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Hi TCG,

The footage you have attached of the Alamo Cube is a lock-off shot. Here the Camera calibrator is the way to go.  The cube is then the Coordinate system. Since it was shot with longer lens there is little parallax in the shot, so it needs to be done very carefully.

If the anything moves, try to get some “pre-roll” footage that starts with a different angle to the cube, that will help to find the the camera path.

Not a complete list of tips, as you can imagine, some good people have filled books with this.
In any case, shoot a lens grid, and measure the object, as well the starting and perhaps end distance of the camera. This place has AFAIK, rectangular floor “tiles”, perhaps a good support to measure the positions. Write down the lens used and the exact type of the camera. If you shoot with RED, the resolution used (not the delivered one) for this shot is crucial as well. In any case, shoot stills from the set and set up. IF possible place some markers in the scene, that can be anything that is dull and different in color, measure those as well.

There is a longer series about Motion and object Tracking here on Cineversity.
https://www.cineversity.com/vidplaytut/motion_tracking_object_tracking_inside_cinema_4d_introduction

Besides that , the Books from Tim Dobbert (2nd Edition) “Matchmoving"and Erica Hornung “The Art and Science of MatchMoving” are my favorites.

Would I say that any shot is solvable, perhaps not, but the more you know and the camera is prepared (receives information), the more it will be possible.

In the moment you have the axis of the cube, you can wrap the cube, but keep in mind, that needs to be composite. So, anyone/anything covering the cube, will have the need to be rotoscoped.

My best wishes

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Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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Posted: 08 September 2017 10:43 AM   [ Ignore ]   [ # 2 ]  
Total Posts:  33
Joined  2012-07-26

Dr. Sassi, Thank you for the wealth of information in your reply!

Have a great weekend!

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Posted: 08 September 2017 01:16 PM   [ Ignore ]   [ # 3 ]  
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You’re very welcome, TCG.

If you have a story board for the project, perhaps I can add more.

In case you have a few minutes to spare, please have a look here:
https://www.cineversity.com/forums/viewthread/2472/

The problem, that often occurs, is that a locked shot just pans around, or even a jib arm shot with normally enough motion—but has framed only far away objects (little parallax or none).
Then the mix of Camera Calibrator (to get the position/orientation) and the Motion Tracking to get the “rotation” of the camera.

Sometimes it can be useful to mount one of these little CCD HD cameras on the main camera, and capture something trackable, preferable 90º to the main view. (CCD as no rolling-shutter, compared to most CMOS. Except the cam has a Motion mount for example to counter act this, or similar…)

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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Posted: 08 September 2017 08:23 PM   [ Ignore ]   [ # 4 ]  
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P.S.:
I made a few trials, and I end up each time with a similar camera.

Perhaps worth a look,

Scene file: (footage not included)
https://www.amazon.com/clouddrive/share/hmSdKxm035a6nakVIbJvQAL3ELVGrQhY6gPn0zBjin9
Screen shot:
https://www.amazon.com/clouddrive/share/TBjQOohT1ZgcUCENHdboBE6tIB4XMkJmsgtNQzR9c6H

Let me know if you have more details.

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Dr. Sassi V. Sassmannshausen Ph.D.

Photography For C4D Artists: 200 Free Tutorials: Texture, Panorama, HDRI, Camera Projection, etc.
https://www.youtube.com/user/DrSassiLA/playlists

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