After Effects tracking camera wrong results

[Abed5CF7]

Hi...

I have a base shot with camera movement (about 20 seconds), I need to add some details to the shot, "Grass-Some buildings..."

I made a layer in PS with the needed details. and put it as a layer in after effects above the based shot.

unfortunately the results after making camera track is wrong.

I  attashed an image to explore the problem, coloring the new layer (pink), as you can see the detail layer scale as 3D following the camera, much more than needed.

any help

[Mylenium]

I'm not clear what you are asking. The only really obvious thing is that a) the footage has terrible quality with lots of compression artifacts and b) the shot is "flat" with very limited contrast, so the tracker may not have enough details to produce a correct stable track. Everything else will require a better explanation.

Mylenium

[Abed5CF7]

Thank you Mylenium for your prompt reply:

the footages are 4K resolution (but I've compressed the image as it's just for explaining the problem), but yes the contrast is limited.

the attched image is in the middle of the result camera track procedure: in the first frame of the sequence, the details layer is in the right place (the red street is above the base one. after 2-3 seconds of the movement, the details layes lose the tracking informations, and, as you see in the image above, scaled much more than the base layer.

hope it's clear now, I can send more images to be more clear if you want

[Rick Gerard]

If you are having problems with a comp, especially a comp with 3D layers, cropped screenshots don't give us anything at all we can use to help you figure out the problem. The workflow description you gave tells me that you don't have any understanding of how the camera tracking works or how to handle parallax and perspective changes.

Every surface you want to replace in the shot you camera track needs a separate layer unless the surface is completely flat. The surfaces need to align with the existing surface. Your shot doesn't need 1 PSD file, it needs at least one layer for each building you added and one layer for each area you need to cover with grass. The objects that you want to cover with grass must be aligned with the surface, the things you want to stand up need to be perpendicular to the ground. You have to build a virtual 3D world that is aligned with the real world the camera is seeing. 

Replacing everything you marked in pink in this shot with one layer is going to require the layer to be 2D and animated so you'll need about 1 hand-painted image for every 2 frames if the movement is fairly fast, and 1 hand-painted image for every 5 or 10 frames when the movement is slow. If there is no camera movement, you only need one image. 

Here are some screenshots from a post I made a long time ago that shows how to track set up the 3D layers to align multiple surfaces in a scene.  I can't find the post, but if I do I'll put up a link. Your composite requires a similar workflow plus some masking (roto) as the perspective on the road changes.

[Abed5CF7]

thank you rick:

you are absolutely right, I have dificult understanding track camera, and I didn't find any clear tutorial for the kind of work I'm doing know. I will try your solution. and I would apreciat it if you can send me any good tutorial for something similar to my project