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Very odd visual glitch... Submerged building facade?

Hi all, 

I just finished processing a 730 img. data set. I’m very happy with how the job-site turned out, but it appears that one side of one of the building is submerged? Funny enough, the facade appears to have rendered beautifully - it’s just angled and sliding into the ground.

I’ve attached a couple images of what I mean. Everything was taken with the same camera from the same altitude and angle. 

Any ideas on what might of caused this? I’m going back out to the jobside again next week, so it’s not a huge deal. But I’d like to avoid having this happen again if possible. 




Wow, we are seeing this A LOT on the forums and I see it in my own projects now.  I previously wonder if there are issues in Pix4D v4 but I rolled back to V3.3 and it got worse so I don’t think it is a software issue.

My thoughts are just weak overlap or shadows/exposure differences in the camera, but also check altitudes in the EXIF data as a friend of mine had his numbers change from morning to afternoon by over 100 feet…gotta love DJI…

I fixed my own project by shooting in consistent sunlight because originally I had 1/3 of the pics in very cloudy conditions and the rest in bright sunshine.  I also bumped up the side overlap to increase automatic tie points.

For me this would be a huge deal, real show stopper and I can’t be sure without the Quality Report and pictures but my guess it isn’t any issue in Pix4D.

Was this project all shot in 1 flight or is a merger of a couple flights?  I’ve had this type of double representation before when capturing data via more than 1 flight and simply added in a few Manual Tie Points on the affected area and the reprocessed.

I’ve also had this and resolved by adding some MTP’s as Aaron described.

Thanks guys… 

I’ve been running around the past two days so I haven’t had a chance to look at the EXIF data, but here’s some more details: 

  1. MTPs did fix the problem. 

  2. This was split into two flights. I did the bulk of the work last Saturday and came back Sunday to add some obliques. 

What concerns me is that since I use Pix4d BIM, I won’t have the ability to add MTPs as it’s all cloud based. I’m going to try flying again this weekend and doing it all in one go and see if that helps.