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3D Tracked Points Drift After Camera is Created

Community Beginner ,
Nov 18, 2017

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Hello All,

I'm having an issue where my 3D tracked points are staying affixed to objects after I scrub thru the timeline after the footage is analyzed.... SO FAR SO GOOD.... but soon as I "Create Null and Camera" those same tracking points drift as footage is played. I've included some screenshots. Any help would be greatly appreciated. Thanks!!

1st Frame After Analysis is run (No camera created yet)

fullsizeoutput_5.jpeg

Scrubbed thru footage - notice tracking points in the same place

fullsizeoutput_6.jpeg

After Camera Created - 1st frame - Tracking point starts out in the correct place

fullsizeoutput_7.jpeg

Scrubbed thru footage after camera created - notice the 3d tracked points drifted up the footage

fullsizeoutput_8.jpeg

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3D Tracked Points Drift After Camera is Created

Community Beginner ,
Nov 18, 2017

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Hello All,

I'm having an issue where my 3D tracked points are staying affixed to objects after I scrub thru the timeline after the footage is analyzed.... SO FAR SO GOOD.... but soon as I "Create Null and Camera" those same tracking points drift as footage is played. I've included some screenshots. Any help would be greatly appreciated. Thanks!!

1st Frame After Analysis is run (No camera created yet)

fullsizeoutput_5.jpeg

Scrubbed thru footage - notice tracking points in the same place

fullsizeoutput_6.jpeg

After Camera Created - 1st frame - Tracking point starts out in the correct place

fullsizeoutput_7.jpeg

Scrubbed thru footage after camera created - notice the 3d tracked points drifted up the footage

fullsizeoutput_8.jpeg

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Most Valuable Participant ,
Nov 18, 2017

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Without any info about critical settings liek comp framerate vs. footage interpretation nobody can tell you much, though this remark in itself may contain the answer already: Check your framerate settings everywhere. Mismatches in that department can easily explain a lot of drift situations.

Mylenium

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Adobe Community Professional ,
Nov 18, 2017

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Is your footage a 3D layer? It can't be. The tracked footage has to be a 2D layer.

The only real good way that I have found to test a Camera track is to:

  1. Set an origin and ground plane somewhere close to where the actual origin and ground plane is you your scene so the target looks like it is attached to the ground - the perspective must be correct
  2. Create a solid and a camera using the origin and ground plane and scrub through the shot to see if the solid sticks to the ground
  3. If you have any doubt that the track is correct you can make the solid bigger, add the Grid Effect and rotate the solid so that it lines up with the perspective of the shot

Once you have a good origin and ground plane you can put as many 3D layers in the scene as you want and they will track perfectly.

One more thing, if there is lens distortion in your footage it must be removed before you track or anything you place in the scene will drift as it approaches the edge of the frame. AE's camera lens is perfect, real lenses can be pretty good. Your shot looks like there is a slight bit of barrel distortion but you are probably Ok.

BTW, cropped screenshots are almost completely useless. I am assuming your footage is a 3D layer because there would have to be another 3D layer selected and transparent and you would have to select render Track Points in the camera tracker to have a 3D cursor in the comp panel. It would probably do you some good to carefully study the Help files and some good tutorials on camera tracking.

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Adobe Employee ,
Dec 19, 2017

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Did our experts' advice assist you 611obrien? Please let us know.

Thanks,Kevin

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New Here ,
Oct 27, 2019

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This is a comment on bad answers...

 

I'm certain most "experts" that replies to questions asked by users who does not possess such immaculate and infinite knowledge in the art of, for instance, After Effects, mean well and are just trying to help. BUT however - many "answers" to fairly simple questions are met with other questions - like have you read the manual, have tou taken a course.... I'm sorry but NO - that is the exact reason to why people ASK. Many users, me being one, try to learn a little here and a little there - we are not aspiring to become AE professionals (because then we would have taken a course or three).

 

I've been looking for answers to two separate "problems" today (I'm new to AE) - and every where I look,  the same person almost telling the persons asking for assistance to either read the manual, stop being ignorant, they do it wrong, start from the tutorials, it can't be done or worse: you dont make any sense asking like you do.

 

How is a person like that even still here "giving advice and support?" - Questions ARE becuse we who ask DO NOT KNOW - we know there is a manual, we have done what we know - but still something does not come out the way we want, thus WE ASK. Please give constructive answers, assume we are stupid, but dont tell us.

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Adobe Community Professional ,
Oct 27, 2019

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John, 

Reading the manual and following a solid training regimen is critical to learning how to use AE. The Home screen in AE has links to some really good training material.

 

This problem, the problem of tracking points not following the expected path is only solved by setting the proper analysis settings in the Camera Tracker and picking the right points. In a shot like this, setting an origin and ground plane and then adding a reference solid and a camera are critical to figuring out how the tracking is going. If you just add a null like the OP said they did, there is no reasonable way to verify that the points that were selected are on the same plane. Most of the time, inexperienced users don't properly set up the tracker or pick the right points. 

 

As far as always saying the same things, that only makes sense. Let me give you an example. I am working on 3 different compositing shots right now where I replace a TV screen on a TV in the shot. The shots all have moving cameras. The shots are from three different angles. The focus shifts as the camera follow the actor. One of the shots requires some rotoscoping. All of the shots involve adding lighting effects from the TV Screen, focus changes, motion tracking of one kind of another. Here's the problem. Every one of these three shots requires a different technique, different tracking techniques, different masking techniques. Do you see where I'm going?

 

Almost every problem you face in After Effects has dozens if not hundreds of possible solutions. Almost every problem that you see with previews, crashes, or any other technical problem also has dozens if not more possible causes and solutions. If we don't have details, most of the time, most of the replies on the forums are just a waste of time. If someone, like the OP on this thread, at least posts screenshots and tries to describe their workflow, we have a chance to help. The more info we have, the more likely it is that we can help solve their problems. Let's take a look at the original post.

 

The first screenshot shows a 3D cursor and the OP says no camera or null is created. This tells me that it is highly likely that the footage layer is 3D. That is an error that would be solved by reading the manual. There could be another 3D layer in the comp but because the screenshot is cropped and no workflow description is offered we don't know. As you look down the stack of screenshots the 3D cursor does not move from the center of the frame so this tells me that the OP has either added a camera to the scene not using the 3D tracker or that the footage layer that was tracked is a 3D layer. Again, reading the manual, or providing details would point this out. 

 

The assumption that tracking markers move over time is also incorrect. Reading the manual explains that. The markers do not move, then attach themselves to details and appear and disappear as time passes. This is also normal.

 

Both Mylenium and I offered a place to start and that is all we could do without more information. 

 

Since you are new, if you have problems and you want answers, give us workflow and system details and screenshots of the entire UI with the modified properties of the layers giving you problems revealed. Then we can help. Just putting up a few cropped screenshots and telling us what you think you see does not help us help you at all.  That's just how it works. 

 

Both Mylenium and I have been using AE for a very long time and helping folks on the forums without compensation for a very long time. Don't be offended if we ask you for more info or tell you to go do some homework. That's how you learn. Just for reference, here's one of my favorite graphics: The J3 and the Shuttle both fly with a stick, both have to be landed by hand, and you need training to safely operate both aircraft, but if something is not going the way you want it to go, it's a lot harder to find the problems in AE than it is in Premiere Pro. You need to do your homework.

Screenshot_2019-10-27 17.35.56_hiEGSa.png

 

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New Here ,
Mar 29, 2020

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Rick, 

 

I have to be honest, I agree with John to a certain degree. I have aboutt 6 yrs or so experience in After Effects, Premiere Pro, well... really the whole Adobe Suite. While I may not be the best in the world, I am certainly above average. Why am I telling you this? Simply to say that I know where you're coming from. There are many times too many variables to give the simple answer. Sometimes more discovery is needeed. 

 

That being said, I spent a lot of time in forums and the like early on before seeking professional training. I had the same frustration as John. I'm a U.S. Marine Veteran and not easily offended. They stripped me of feelings years ago, but I can still spot someone being coy. 

 

I'm not saying that's your take on this question. If I were a betting man I'd say that John's been thumped on the head in these forums a few times and has gotten on the short side of his patience. I have been told in these forums to "go read a book", etc... Or lectured about how little I know. Talk about irony... That's why I came! Haha. 

 

I would just encourage you or anyone else to refrain from posting stuff like, "The assumption that tracking markers move over time is also incorrect. Reading the manual explains that." I'm pretty sure that's exactly what John's referreing to. We could all have the answers if we just piled enough manuals next to our desk. But isn't that why the forum is here? And can we stop with getting the last dig in too. "You need to do your homework."  Really? We can be right, or we can be rich (friends, family, money), but if it's right we choose we'll likely have very little of the either. Being right has a way of pushing out everything else. 

 

Thats my 2 cents as an intermediate who resonates with John's comments anyway. And BTW, I do genuinely appreciate all that you and the others bring to the forum. Despite how my diatribe may sound it's mostly all good that I see. I've gotten Gold out of here and its saved my butt a few times. 

 

All the best,

Chad

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