Impossible 3D Camera Tracking?

[Guest]

Hi,

I am very sorry that my first post is a question and a plead to help. I hope I can give back after that, but I am stuck with what it seems a very difficult 3D camera track.

Camera faces down and while moving downwards is changing perspective to

looking straight forward.

Here is the clip in question:

https://adobe.ly/2o1udiX

(original footage is in 4k)

If I mask out the bed/two people moving I once got a decent track, although I had the feeling the camera position is not always right. I tried to improve by making the masked out area tighter or bigger and it only got worse. I need to do this three times for three different takes by the way!

I am spreading particles with Trapcode Particular in the room that are moving upwards.

My problem is that the tracked camera has some jittering, as if the camera has sub-pixel shakiness, although it doesnt really.

I know one problem is the two people and their shadows that is confusing for After Effects, but when masked out intirely I still seem to have some jitter and random shakes and the track gets worse the more I mask out, naturally.

I am using AE CC 2017, updated to the newest version btw. I tried tracking in different resolutions: 4k and 720p, but it doesnt really matter it seems.

Does anybody have any tips on match moving this for 3D integration?

I tried Mocha Pro but it doesnt even solve the camera. Currently in contact with support of Imagineer Systems.

But I thought, I would ask here too.

Thanks for any help!

Manuel

[Mylenium]

Same old, same old: There's simply not enough distinct patterns and barely any motion. It's all a sea of whites and browns. This will never solve properly. You would have to reconstruct and calibrate the scene manually in a tool like Syntheyes, but even there it probably would require manual keyframing.

Mylenium

[Guest]

I see, thanks for the reply!

I was just wondering: the 3d camera I get is alright in the sense that it matches the 3D space pretty ok, but camera jittering is unnerving and I was wondering if there is a way to smooth out the motion; basically get rid of the small jitters from time to time, without having to correct that by hand.

[Rick Gerard]

If you are trying to attach an Particular (trapcode) emitter to some movement in the you should be using motion tracking and not Camera Tracking. You could do it with Mocha or even Adobe's Track Motion.

If you are trying to smooth out camera moves you should be using Warp Stabilizer. I think your entire approach to the problem using 3D space is wrong.

[Guest]

Rick, let me explain again so you better understand whats going on:

I am recreating the 3D space the scene was shot in so that I can have particles moving around in that space.

Particles are not derived from an emitter attached to a Null, nor do I want to smooth out the original camera motion.

I was talking about the 3D camera, that is jittering because of miscalculations of AE.

See my try here:

https://adobe.ly/2oMfImA

You can see how sometimes the 3D camera is jittering.

I tried smoothing out camera position with the smoother but this function is disabled for orientation, which also adds to this jitter. I am thinking about just deleting every second keyframe for camera orientation, but was wondering if there are better ways to smooth this jittery camera.

[Roei Tzoref]

try using a smooth expression to smooth the orientation parameter

see if that helps

[Guest]

Tried that but it seems that the camera then always change between 0° and 360° somehow and face into the other direction or so...

[Roei Tzoref]

the only thing left is to try to get a better track. how much pixel error did you get? if you have angle of view information you can try to dial it in. other than that this maybe a case for a more advanced camera tracker like Mylenium suggested before. I would also wait for Rick to see if he has an idea in mind.

[Guest]

average error is always around 0,47pixels

I will try to track again with set angle of view (I guess that is the full frame lens info in mm?).

do you know of any script that could delete every nth keyframe. I am looking around the  net, but cant find anything.

[Roei Tzoref]

a search found this:

https://forums.creativecow.net/thread/227/12027

if that doesn't work, I would advise calling out to Dan again for a tailored solution.

[Guest · Accepted solution]

Thanks so much!

That kind of solves the problem.

I only found a similar thread but couldnt apply the script to the orientation. Camera orientation is a strange beast. If I could have separated the different axises I could have smoothed out the keyframes, I guess. But that wasnt possible.

tracking isnt perfect but smoothing out motion helps, everything else I have to fix manually by adjusting world space and stuff with Particular.

For others:

I deleted similar keyframes of the camera position with the Smoother function;

deleted every second keyframe of camera orientation with this script:

{

var myComp = app.project.activeItem;

if (myComp && myComp instanceof CompItem){

var myLayers = myComp.selectedLayers;

if (myLayers.length > 0){

var myLayer = myLayers[0];

var myProperty = myLayer.property("Orientation");

for (var i = myProperty.numKeys; i > 0; i--){

if (i%2 == 0) myProperty.removeKey(i);

}

}else{

alert("No layer selected");

}

}else{

alert ("No comp selected");

}

}

[Roei Tzoref]

Glad we got you sorted. If you want, you could send a link later on where can we watch your masterpiece,

[Rick Gerard]

I probably would have motion stabilized scale and rotation and not used camera tracking for this shot. Then I would have applied Trapcode Particular to a solid, adjusted the particle dispersement, then used one of my often used animation presets to add a null to the project and used parenting and the expressions to put the movement back in the Motion Stabilized shot (you name the stabilized footage "stabilized" and then added the motion to the solid. It would have taken a lot less time than camera tracking and then trying to fix the camera track, and it would have looked exactly the same with this kind of shot.

If you wanted to get rid of the subtle camera operating errors you could use Warp Stabilize first and then add in the particles.

Your method will work but IMHO it was involves a lot more fiddling around than is necessary.

One other thing - the shot is pretty racy for the 14 year olds that frequent this site. Before posting that kind of content I would warn the forum goers that you are posting adult content.

[Guest]

mmmh, but what about the camera motion in space. I mean we have a huge difference in point of view comparing the start and the end. I really want the particles to feel like they are part of the space the clip was shot in so just stabilzing it wouldnt work, dont you think? The camera is basically moving around the particles from top to bottom then and I would have needed to adjust world space or the camera manually everytime it changes perspective. Seems fidgety to me too

I didnt think the footage is racy - you dont see any nudity or explicit things. If I can edit my post, I would put in a warning. Any way to do that?

Anyway, for people who are interested in this project - if I remember I will make an update here -, but you can also like our Facebook page for news and info about it:

https://www.facebook.com/UnstillbarFilm/

[Rick Gerard]

The technique takes care of the camera motion perfectly. Before Camera Tracking I did hundreds of composites using this technique. Similar techniques were used in a huge number of feature films. If you eliminate all camera motion in a scene then you have a stable canvas you can use to create your composite. When you put the motion back in the scene and add the camera motion to the composite including scale and rotation everything works and your composite is seamless. Check out this example. The principals apply.

Because you are using particular another technique would have been to motion track part of the scene where you wanted the emitter to be centered, apply that motion track to a light, then attached the emitter to the light. This would also give you a nearly perfect match to the camera movement. With just a couple of keyframes for Z position for the light you could have matched up the move perfectly.

My point is that there are many ways to do a composite and the key to staying on time, staying on or even under budget, and making a living requires you to explore all possibilities and use the technique that gives the most acceptable results in the least amount of time. I am not saying your technique would not work, I'm just trying to point out another solution that would give you the same result with a lot less work in a lot less time. I've been doing this kind of work for 47 years and I've seen hundreds of my associates go broke because they could not figure out how to look at a problem and come up with the most efficient solution.

On another point, your definition of explicit is very liberal. I don't know any responsible parent that would want their 14 year old child watching that clip. The content is definitely adult.

[Guest]

I totally get what you mean with that suggested workflow and I think it would work for this scene too, but it would also mean I would have to manually adjust particulars world coordinates. you see, I want the particles to flow upwards when the camera is facing downwards and then when the camera is at the lowest position the particles still have to flow upwards, not towards the camera. this means I need a real 3d camera that is moving around in almost the same space as the shot.

If I just track the camera motion (that is X and Y), then the particles would constantly flow towards the camera and not give the feeling that we are moving around the particles in space.

or am I missing something here?

I really do appreciate your advice though! thanks a lot!

ok, sure, maybe the clip is not for kids, but from my German point of view it is for people over 12 (thats how it would probably be rated here in Germany/Europe). I didnt think that kids frequent this forum; but sure, everybody can get access to this, so an advice is not bad. I cant seem to edit my post though. not possible here?