How to capture trees in 3D? My model does not render them

I need help. I’ve found this issue in all of my models where WebODM is not rendering the trees on a property. I’m happy with the results of the rest of the model, but behind the house there is a small stand of trees that seem to just vanish to a void.

Is there a setting I should be using to capture this information? I chose in options ‘3D model’ for the default task outputs.

Here is a snap shot of the void of trees

Here’s a plan view of what that stand of trees should look like

Here are the images I am using
https://drive.google.com/drive/folders/1luVoZgPLHDv0ZFmbJgvtI3Osy8aGNO7S?usp=sharing

Thanks for any feedback.

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You might need to bump up feature-quality, min-num-features, matcher-neighbors to get that tree stand.

However, that is oftentimes tricky scenery to reconstruct, so if the above doesn’t help, you might need a refly with tighter overlap/sidelap over the trees.

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As suggested, higher overlap and more robust processing setting may help, but trees are generally a huge challenge for photogrammetry and it is particularly hard when flying over decidous trees in winter.

If you think about what the photogrammetry code has to do, it has to find <1cm thick twigs in multiple images seen from very far away at different angles where there is tons of occlusion, everything looks the same and the branches are almost always moving around. This is a really hard (and still somewhat unsolved) computer vision problem.

Flying when there is no wind is helpful, but even if it isn’t very windy there is always going to be some air movement. Also, if you think about the math, even if your GSD is 1cm, that is likely thicker than many of of the ends of branches in a tree with no leaves, so again, hard for the computer to figure out.

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Try setting the pc-filter = 0 too. It’s likely to generate more noise but it will help in building those spindly features. You can later remove the noise with PDAL or by hand in cloud compare.

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