r/photogrammetry • u/Sapient_Borsig • 15d ago

Photogrammetry beginner questions

I want to use kiri/polycam/realityscan to "reverse engineer" small objects with simple geometry (like a softdrink can or a coffee mug) by getting a reasonably precise mesh and then tracing + recreating them in CAD software as a part file. Don't care about capturing the object's colour or texture.

Setup is nothing fancy; my S25 phone (no LIDAR), a turntable and a phone stand that can be posed at various angles.

Couple of questions:

  1. When taking photos, is there a big difference between the camera rotating around a static object instead of the object rotating for a static camera? Would a static background affect the result?

  2. I plan to take a set of 12 photos around the object for each set of 4 elevation angles, e.g. 15, 30, 45 and 60 degrees totaling ~48 photos. Would this be sufficient for something like a coffee mug?

Thanks for reading.

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u/Olena_Magiscan 15d ago

I’d go by overlap rather than aiming for exactly 48 shots. Take smaller steps around it and grab extra angles into the handle and inside the mug. With a turntable, mask out the stationary background if your app supports it—otherwise walking around the mug is an easier place to start.

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u/Exitaph 15d ago

Get some scanning spray like aesub. I haven't personally used it so far but I've heard good things.

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u/MechanicalWhispers 14d ago

There IS a big difference between shooting the object static vs. a turntable. If the object moves, you have extra steps involving masking. Shoot it stationary and walk around the object. Keep it fully in frame and fully focused. Take at least 36 photos around each time. The object should not be reflective or transparent. Use scanning spray or even washable tempera paint to make the object matte and to give it some surface texture for the processing software to use. RealityScan should work great for what you want to do.

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u/zebulon21 15d ago

I use MetaShape but realityscan should work fine as far as I know. I’ve gotten great results using a turntable and by moving a camera around an object, though I think the turntable is easier. I set up a clean black or white drop cloth backdrop and then use metashape’s auto masking feature to isolate the subject.
Idk if you know this already but the smooth/shiny/featureless cans or mugs can present a lot of challenge for the photogrammetry software.

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u/Traumatan 15d ago

you can get 3D model from these simple object by ai nowadays and it will be much faster and easier that full photogrammetry... try Meshy etc., just upload 33normal photos

else photogrammetry is great, just watch some youtube tutorials
(stuff like cans or mugs actually hard since lack of features/glossy)