3D Tracker places camera below horizon

[WShawn]

I'm attempting to track a pretty simple aerial shot of some turbines. C4D easily produces good 2D tracks (ignoring the spinning blades), but when I run the 3D solve it places the camera below the horizon, acting like the sea in the distance is closer to the camera than the turbines in the foreground. Adding various constraints orients the ground to be mostly level, but the camera stays under the ground looking up rather than looking down from above.

Is there some trick to forcing the camera into the proper position and orientation here? My only way around this so far is to do the track in After Effects (which works as expected) and export that comp to a C4D file.

Here's the scene file and clip.

https://www.dropbox.com/scl/fi/vtsok6olt7x01pvuvkjed/TurbineTrackTest.zip?rlkey=3ecq15yqoqf4uacpvgtzhfovr&dl=0

Best.

Shawn Marshall
Marshall Arts Motion Graphics

[Dr. Sassi]

Hi Shawn,

Sorry, there's no magical trick. But I hope this helps a little bit.
CV4_2024_drs_24_TRwm_01.c4d

Is there a more extended clip of this shot?
Do you have a lens distortion raster shot?
Any camera lens and sensor data?

All the best

[Dr. Sassi]

P.S.:

Perhaps that helps. I do not know how the "floor" tilts, so I left that alone.
The figures are in the correct position but eyeballed to be upright.

https://stcineversityprod02.blob.core.windows.net/$web/Cineversity_Forum_Support/2024_PROJECTS_DRS/20240324_CV4_2024_drs_24_TRsy_01.zip

[WShawn]

Thanks again for your reply. I used to use Syntheyes back when it was the only affordable motion tracking software out there, and I think it had a feature that would quickly correct a track when it thought things in the distance were in the front. I guess C4D doesn't have a similar feature. I tried a longer clip but got the same results. This is an Adobe Stock clip, and it seems unlikely it contains metadata regarding the lens. After Effects can track it with some masking and massaging.

Cheers!

Shawn

[Dr. Sassi]

Hi Shawn,

Yes, I explored it last night and even put it upside down (who knows? It's one of my mantras). I de-distored it in several ways to see if someone had done something to it, but with mostly no geometry in it, it's hard to tell.

I have shot with drones and the lens distortion grid. I always got solid results with Cinema 4D, but I had at least ten seconds each time, with more movement before and after the center content. I typically do not touch stock footage for various reasons, and your example added one more to it; thank you!

Yes, the first file was done with Ae, and the second was an older version of Syntheyes (I rarely used it since I get most of my shots done with Cinema 4D). But yes, Syntheyes rocks (I took a dozen ten-part courses about it over the years at FXPHD and was always amazed at what Victor Wolansky could pull off with it, and he pretty much always started with the impossible shot.)
In the past 25 years, I have worked with many trackers and am curious about where we will go next.

My best wishes for your project