After Effects 3d Camera Track, need additional tracking points

[Mavrizzle]

I have footage of the subject walking forwards with the camera and need a 3d track of it.

After effects only recognizes the wall in the background and not the grid like pattern on the ground (First Picture).

Therefore I can not really add in 3d objects realisticly as they move as if they were attached to the background instead of  actually sitting in 3d space.

I have already checked the "detailed analysis" option under the advanced section, which has just resulted in more points on the wall.

I have also tried to make the lines on the ground more visible by pulling down the shadows and adding some sharpness and then precomposing it, but when I tried tracking that footage after effects said "unable to acquire rendered frame" (Second Picture)

Any Ideas?

Thanks in advance, Maverick

[Towerguy]

Hi Maverick. You can precompose the vid and go crazy with effects like Contrast, Find Edges, Invert etc. anything that will really punch in the detail, it doesn't matter how awful it looks- track in the main comp and then turn off the effects in the precomp. I presume you are already masking out the moving figure.

[Mavrizzle]

Thanks for the quick response. I have tried that, but as I said an error occurred (2.png). I have not tried to mask out the person yet, good tip but I think it would not solve this specific issue, might try that later though 🙂

[Rick Gerard]

It would really help if we knew what you were trying to achieve. 

There isn't much geometry in that shot and if the camera is just moving straight back or panning you might not get any perspective.

I duplicate footage in the timeline then trim it or add effects to increase contrast and add detail and even do some masking to remove things that move like the guy in the frame all the time. The duplicate layer with effects is Pre-composed and Camera tracker runs on the pre-comp. Once the camera and some reference solids are in the scene I either delete the pre-comp from the timeline or turn it off. It has served its purpose. 

Give us a detailed description of what you are trying to achieve and what the camera move looks like and maybe we can help figure out a solution.

 

[Mavrizzle]

Thanks for your response! As I mentioned before, I have already tried to "add effects to increase contrast and add detail" however, after effects then gives me the following error message: "unable to acquire rendered frame".

The camera movement is a constant pull backwards with a pan left and right once.

I want add in an obeject (specificly the moon and mars") next to the person talking to the camera and keep them in the background as he walks past them (check example pictures)

  

[Mukaida]

The result may not change, but if you switch the Shot Type to Specify Angle of View and enter the horizontal angle of the camera, the tracking accuracy will increase.

結果は変わらないかもしれませんが、Shot TypeをSpecify Angle of View に切り替えて、カメラの水平画角を入力するとトラッキング精度が上がります。

[Rick Gerard]

Try Find Edges and mask out your actor. I just pre-composed a left to right move on the still and got a lot of tracking markers on the ground. It solved as a pan because that's what I was simulating but Find Edges should work pretty well.

 

[Mavrizzle]

 

Thanks for being so active 🙂 However, I still keep getting the message "unable to acquire rendered frame whenever I try to track the footage after altering it in any way (and precomposing it)

[Rick Gerard]

What format is the original footage? If you pre-compose and move all attributes it should work just fine. It also might be a good idea to break up the shot into sections where one of the spheres states in the shot. You can have a bunch of cameras in a single comp, just set in and out points or pre-compose to build the final shot. Most important - don't try and do everything on one layer.

[Mavrizzle]

Find Edges worked, for some reason lumetri seemed to make it fail every time. The track did not go that well, but that´s probably just because of my footage specifically. Thanks anyways. I have now handtracked some parts myself as a work around :I

[Rick Gerard]

There is another option. Corner Pin Track the floor in Mocha AE making sure to have perspective selected. Verify the corner pin track in Mocha AE is valid by adjusting the surface and adding a grid. Make the surface as large as possible. When you get the corner pin track done in Mocha apply it to a solid layer in AE, then add a grid to the solid layer. Make Adjust the grid so you get a nice contrast (Grid must be above Corner Pin). Now Precompose that and Run Camera Track on the nested comp. This will give you the original background which already gave you some geometry and an accurate fake floor with a grid that will give you the detail you need to get camera track to work properly.  Mocha looks like this: Two Splines on one layer + the surface adjusted to match the perspective on the floor and then expanded to include all of the floor, and a grid applied to check the accuracy of the track:

Then back in the main comp corner pin is applied to the grid to give you some detailed geometry and hide a lot of the actor's body from the trackers.

I've used this technique a bunch of times and it works very well.