• Global community
    • Language:
      • Deutsch
      • English
      • Español
      • Français
      • Português
  • 日本語コミュニティ
    Dedicated community for Japanese speakers
  • 한국 커뮤니티
    Dedicated community for Korean speakers
Exit
0

Issue with perspective corner pin tracking

Enthusiast ,
Dec 05, 2017 Dec 05, 2017

Copy link to clipboard

Copied

I'm trying to do a perspective corner pin (or parallel corner pin) track of a video.

If you look at a tutorial video it shows that to do perspective corner pin track you select the layer, go to "track motion" and then in Track Type you select "perspective corner pin". In the demo video it will then shown something like:

Track Point 1 ----- Track Point 2

Track Point 3 ----- Track Point 4

(so basically a square with the 4 corner points ready for positioning).

But when I do the above (selecting "Perspective corner pin") the track points get created like below:

perspective-corner-pin-initial-positions.jpg

The initially created points for "perspective corner pin" aren't in a square but are in the above shape. It is also hard to move the points because I assume it's doing some validation. What is wrong and how can I fix it so it always defaults the track points the the correct "square" shape with point 2 to the right of point 1 etc?

This is using AECC2017. Also the video I'm using it on says the pixel aspect ratio is "non-square 1.00:1" (what AE interpreted it as) - in case that has anything to do with it.

Views

4.9K

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines

correct answers 1 Correct answer

Enthusiast , Dec 05, 2017 Dec 05, 2017

It's now stated initialising the points correctly again but (after trying various things like deleting the clip, re-importing, changing the pixel aspect ratio then back to how it was) and something made it start initialising the points correctly. Though I'd like to know exactly why it initialised them like above so I now for sure (without having to delete/re-import the clip etc.). Also, is it a bug that has been fixed in the latest AE?

Votes

Translate

Translate
Enthusiast ,
Dec 05, 2017 Dec 05, 2017

Copy link to clipboard

Copied

It's now stated initialising the points correctly again but (after trying various things like deleting the clip, re-importing, changing the pixel aspect ratio then back to how it was) and something made it start initialising the points correctly. Though I'd like to know exactly why it initialised them like above so I now for sure (without having to delete/re-import the clip etc.). Also, is it a bug that has been fixed in the latest AE?

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Community Expert ,
Dec 05, 2017 Dec 05, 2017

Copy link to clipboard

Copied

Where the points start is not really that important. The important thing when using AE's Motion Tracking is to select enough detail with the inner box to get a good track. The more highly compressed your footage, the more motion blur or general softness you have in the shot the bigger the inner box needs to be. With consumer grade cameras and especially video from smartphones the default detail area is not big enough. I find that it usually has to be about twice as big for non-pro footage. You also have to make sure that the Search Area, the outside box, is big enough to account for any and all camera or object movement in the shot between frames. The bigger the search area and detail area are the longer it will take to track, but a slow track is much better than a bad track that takes you hours to fix.

Also, if you need to adjust the search area or detail area during the track make sure that you hold down the Ctrl/Cmnd key when you make the adjustments and make sure that the attach point, the little cross in the middle does not move.

Another hint, if you are trying to repair a track and you have show all keyframes or even show multiple keyframes selected it can be really difficult to see what is going on. When I have a Motion Track I need to repair I open up preferences and set show keyframes to 2 or 3 or even turn keyframes off. You want to watch the attach point, the little + in the middle. That is not what you are tracking, that is where the center of the position for that tracker will be. Sometimes the track will jump quite a bit between frames. You can often fix this by stopping the track and moving back a frame or two and then tracking again one frame at a time.

If you have any problems getting a good track then try corner pin tracking in Mocha AE. With about 90% of the shots I track I get a better result in less time using Mocha AE.

One more point, and I make this often. Be sure and vet your trainer. There are a huge number of tutorials on the web by amateurs that don't know what they are doing. They can give bad advice and teach inefficient workflows that will foul up your projects and waste your time. Make sure they know what they are talking about. If the tutorial you are watching did not start off by suggesting that you change to the Motion Tracking workspace I would worry about the experience level of the person doing the tutorial. Check them out.

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Enthusiast ,
Dec 06, 2017 Dec 06, 2017

Copy link to clipboard

Copied

re: "Where the points start is not really that important"

They are important when they start off like in the above screenshot (instead of when they start off correctly in a squareish way with point 2 to the right of point 1) because when they start off like above it's really hard to move them to their correct position because of what seems like AE's validation. ie. you can maybe move one a few pixels and then it just stops moving, as though it is doing validation saying "this point's x/y must be <= this point's x/y" and ">= this point's x/y". When the points are initialised correctly you can easily move them around.

So it seems like a bug or something that causes the points to sometimes be initialised like the above screenshot, and when they are they are very difficult to move the various windows more than a few pixels.

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
Adobe Employee ,
Dec 20, 2017 Dec 20, 2017

Copy link to clipboard

Copied

Hi A.I.1,

Sounds like you solved your issue but you still have problems with the implementation of the point tracker. Can you please file those bugs here?

Thanks,
Kevin

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
New Here ,
Dec 19, 2021 Dec 19, 2021

Copy link to clipboard

Copied

Hey this really helped me a lot when I was trying to track a very small object that I  imported from Blender. I had A tv doing a 360 rotation , but I wanted to make sure that what I put on the tv screen ( through roto-scoping the screen out and doing a replacment ) kept a consistent perspective as the tv fliped. 

 

By enlarging the both the inner and outer square I was able to get a  much better track. I aslo went to options and changed the tracking samples to RGB(because the tv is red and back ground is a trasparent plate). 

 

For context I had a tv flying through outer space doing 360 flips. I wanted to make sure the picture kept to perspective using the perspective tracker. This was not an easy task for me... as I'm new and this task seems more intermediate. Anyway this info helped a lot, thanks Rick

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines
New Here ,
Jun 05, 2024 Jun 05, 2024

Copy link to clipboard

Copied

LATEST

Hi there, seems the issue you have got is still not fixed in After Effects. I just got the same problem. Can anyone help me to fix that?
The Tracking Points are in the same shape and I can't move them. 

Votes

Translate

Translate

Report

Report
Community guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
community guidelines