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I have done my research and know that a reason for this might be that I don't have eight good trackers. However, I do have at least eight trackers in every frame of the shot, and I still get the same message everytime (some data failed to reconstruct, see console for more details). Also, where can I find the console? I looked at the python console and the info in the scripting work space, but I couldn't find anything. I also have no idea (besides eyeballing it in the tracker preview window) whether my trackers are good or not, since the solve error changes everytime I click on solve. I have keyframe unchecked, it still changes everytime I do something. For a short periodt of time it seemed to be working just fine, I could change the weights of the trackers and managed to drop the solve error to about 1.9, but suddenly I began getting random numbers again, over 100 etc, even though I didn't change anything but adjust the weight of another tracker. Sometimes solve error equals "nan". What does THAT mean? Some trackers are highlighted in yellow, some in red when I hit A to select all (I have info turned on). First I thought it was because those trackers are the ones that failed and kept refining them, but then I realised that if I select any red tracker, unselect it and select all again it turns yellow, and others turn red. I'm so confused. Checking the tripod box doesn't make it better either. Does anyone know what I can do to get a half decent track out of this?

Also, does anyone know where I can upload the .blend file? I tried a few but the file size is about 64201KB and that's too large for most sites. I can only provide screenshots for now.

enter image description here

More screenshots of settings

Link to the footage I'm using: https://vimeo.com/419597015 (password is "tracking issue")

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Everytime you get the "some data failed to reconstruct" error it means only one thing: tracking is not accurate.

Without seeing the video file is hard to determine what is wrong. Post it in some video sharing site and share the link as part of your original question.

Vague advise is the only thing that is left until you can give more information:

If the video is blurry, shaky or has any kind of motion blur distortion you will have a hard time getting good results when tracking.

Yes, you need at least 8 good trackers,and 8 trackers means 8 solid trackers on a portion of the video where there is useful information. Use the keyframe option so that blender determines what section that is.

Check your trackers one by one on the track window to see if they are slipping or jumping about.

Example of bad tracking:

enter image description here

Accurate tracking:

enter image description here

Make sure that you are using the correct solve model. If the camera is stationary, and the camera is just panning, and tilting, but not being displaced you need to use "tripod" as the solve model, and you will get no 3D information.

There are many tools to help you figure out what is wrong(like the graphs with green, red and blue lines) use them.

Motion Tracking. What do the graphs represent and how are they useful?

There is a very detailed post in this site to help you troubleshoot tracking:

How can I get better results when doing camera motion tracking?

Read it carefuly and follow the links on that post. It makes no sense to repeat all of the info here.

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  • $\begingroup$ Thanks for answering! Yes, I've read that post before, it doesn't really help with my problem though. I know all of this information already, what I don't understand is why Blender is acting so unpredictably. I have refined my trackers and done everything I can do, but I don't even understand WHY these things are happening (the very random solve errors when I'm just changing the weight, "nan" as solve errors, etc). I put a link to the footage in my original post. I know the trackers aren't good enough, but that still doesn't explain Blender's arbitrary behaviour. $\endgroup$
    – Crying Clouds
    May 17, 2020 at 15:41
  • $\begingroup$ random solve errors and unpredictable or arbtitrary whatever, is all caused by poor tracking. The video you posted has very few features you can track accurately. When doing green screen all that matters are the edges around the person. Add more tracking markers on the fabric when you shoot. Especially at the beginning of the shot and in the creases of the step or bench or whatever the person is standing on. $\endgroup$
    – no-can-do
    May 17, 2020 at 15:49
  • $\begingroup$ Okay, I'll give that a try. Thanks again! $\endgroup$
    – Crying Clouds
    May 17, 2020 at 15:56
  • $\begingroup$ the most important thing to determine depth is to determine parallax, where trackers move at different rates based on the distance to the camera. $\endgroup$
    – no-can-do
    May 17, 2020 at 15:59
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It's possible that you've got trackers tracking on frame 0, which you usually don't want. You can select all of the trackers on frame 1 with "A" and then clear before (the option is in the tracking dropdown).

I've attached the following picture to make it a bit clearer how to find this section (apologies for the messy, garish numbering). First, go into your motion tracking tab. The menus will be all set up correctly there. Then, on the left hand side, select "Track". Third, scroll down until you find "track", and the option to clear the track path before the current frame is there.enter image description here

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    $\begingroup$ Hi Kyle, this is a good answer. Do you think you could provide an image of the menu you reference? $\endgroup$
    – Allen Simpson
    Jan 11, 2021 at 5:15
  • $\begingroup$ Sure Allen. I've updated it with an image. Good luck! $\endgroup$
    – Kyle
    Jan 12, 2021 at 18:21

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