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More Mocha Problems

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Tyler StegallMore Mocha Problems
by on Nov 16, 2013 at 9:03:11 pm

As reference, I am trying to track this chessboard, as the camera slowly pans up.

No matter how many squares I seem to track, and all on the same layer mind you, the track starts to slip and fail.

This is getting frustrating as I'm worried I won't be able to get the hang of this in time to finish my project. Will it be easy to use the camera solve with this, so I could get 3D null objects and put some 3D layers on it?

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Ridley WalkerRe: More Mocha Problems
by on Nov 17, 2013 at 3:20:44 pm

I notice you do not have Shear and Perspective checked for the track.

Does the tracking still fail when these are enabled?

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Roland R. KahlenbergRe: More Mocha Problems
by on Nov 18, 2013 at 1:05:43 pm

Tyler, you've still got the Minimum % Pixels Used set too low. I did suggest, previously, that you increase this to at least 90%.

You've also created a large tracking spline around smaller ones. The smaller tracking splines effectively create 'holdout tracking areas' - the latter are areas that are cut off from the larger tracking spline. They do not add to the tracking area. Rather, they do the opposite of what I think you are intending to achieve with the smaller tracking splines.

Additionally, the smaller tracking splines do encompass an area of high contrast. Selecting an area with similar texture, color or shape does not provide the tracking engine with a sufficiently good target to track.

You will want your tracking splines to encompass an area that includes a high contrast, planar object. To do this, create a tracking spline that covers, exactly, one of the white squares. Then increase the size of the tracking spline such that the new area also encompasses a little of the surround area. You now have a high-contrast area, defined by the tracking spline, for the tracking engine to engage with.

I almost forgot! Only mochaPro has the 3D Camera Solve module. mochaAE does provide a camera solve feature. Have you tried AE's 3D Camera Tracker?


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Tyler StegallRe: More Mocha Problems
by on Nov 18, 2013 at 10:38:49 pm
Last Edited By Tyler Stegall on Nov 18, 2013 at 11:33:38 pm

Alright, so you suggest that I should just highlight one of the squares, and instead of perfectly tracking it with a box, make that box bigger so it is touching other squares that surround it?

I should also note that I do indeed have access to the version of Mocha with a camera solver and I'm also running into issues. My tracks of individual squares (That I have just got working at the time of this edit) and the track of the board itself don't produce an accurate camera solve. I can only manage to get up to 70 percent solve. does anyone have any advice on how, or if the image I provided is enough to have a 3D solve.

And when I do bring that solve into after effects, the solve seems to work very well until the camera movement begins, as the camera just tracks up, for some reason the nulls created don't stay where they should on the board, they rise off it, even though this doesn't happen in my track preview in Mocha.

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Ross ShainRe: More Mocha Problems
by on Nov 20, 2013 at 3:59:07 pm

A few thoughts:

If the camera is moving, you need at least 2 surfaces tracked to get a 3D camera solve to work in mocha's 3D solver.

Increase the % of pixels tracked parameter to get the best track.

Also - it sounds like the world is not oriented correctly for the 3D solve? You may want to look at some tutorials to make sure that your camera and objects are positioned in the right space.

This is some good reference:

For 2D planar tracking, the blue surface is the ultimate reference for tracking quality.

For 3D solving, first you want to get good surface results than, mutli-select and hit 3D solve. You want to get a quality of at least 85 or higher.

This all said, as powerful as mocha's planar tracker is, there are shots that are more appropriate for point or camera tracks. A chess board with only high contrast black & white is a good example as mocha tracks "texture" while other trackers use high contrast point.

Best of luck,

Ross Shain
Imagineer Systems

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Tyler StegallRe: More Mocha Problems
by on Nov 20, 2013 at 4:05:52 pm

Thanks for the reply. After messing with settings I actually got the track to work really well. I also managed to get a PTZ solve working. However, when I bring the data into after effects, once the camera starts moving, this happens:

As you can see. The Nulls are exactly where I would like them to be... they just don't stay there.

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Ross ShainRe: More Mocha Problems
by on Nov 20, 2013 at 4:11:19 pm

Is the camera on a tripod? PTZ is only valid for Pan, Tilt, zoom where the camera is fixed. Otherwise you do need multi-planes selected for the other solving modes.

I would still recommend looking into the Orient World video for the ground plane.

Have you tried the AE camera tracker? Like I said, there are def shots that are more suitable for other trackers?

Ross Shain
Imagineer Systems

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Tyler StegallRe: More Mocha Problems
by on Nov 20, 2013 at 4:14:45 pm

I think you are right, I won't be able to use Mocha for some of my shots. I actually just got the 3D camera tracker working. I'm watching the video on Orient world right now. The one thing I don't understand, is how to take the 3D point data that it AE generates, and put a ground plane on the chessboard, could you point me in the right direction for figuring that out?

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Ross ShainRe: More Mocha Problems
by on Nov 20, 2013 at 4:38:58 pm

I could be wrong, but believe that that in the very latest update of AE CC, the 3D camera tracker has a ground plane tool.


Ross Shain
Imagineer Systems

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