[jcvhaarst]

What kind of image quality would one need to get something useful out of this. Useful : Create a 3d model of a house with surrounding trees, so I can see the effect of those trees on a planned solar installation. Or create a 3d model of a garden to see where the sun and shadow are over the course of the year.

[fsloth]

The better the photograph, the better the output quality. Photogrammetric output will always have noise. Some materials don't really contain any surface details that the algorithms could use to attach feature points to, so they will be blank. Large white walls and large windows are especially difficult.

Don't crop the photos. Prefer slight underexposition. For each detail you want to capture, have it visible at least in three photos. Capture photos from different position (ie. rather move yourself than just turn the camera) with at least 30% - 50% overlap between photos.

You can find lots of tutorial in the internet. Search term that hits gold is 'photogrammetry tutorial'. For example:

https://medium.com/realities-io/getting-started-with-photogr...

If you just want to try out the technique, I suggest you download the free test version of Zephyr 3D. You can just give it a bunch of photos and it does a fairly sane ops with the default options.

https://www.3dflow.net/3df-zephyr-pro-3d-models-from-photos/

If you like it, you can start experimenting with free and commercial tools including the one in the topic of this thread (see my other post in this thread for some other photogrammetric tools).

If you have a large set of photos you will start to need a fairly beefy computer with tens of gigs of RAM the least. But, you can get pretty nice results for e.g. just a single house with just a regular modern desktop PC.

[bronco21016]

I love the idea of your proposed application. However, I don’t see it as a problem needing solving. It’s fairly easy to survey a solar installation and potential shadows using basic trigonometry and sun charts. I would imagine many solar installers can do this in under an hour.

I was running some experiments with Drone Deploy and my DJI Mavic to document road damage and flooding in my neighborhood because the city has neglected to maintain our storm water infrastructure. Perhaps I wasn’t using high enough overlap but I found I could not get quality orthophotos at the desired resolution because of too many trees. Using a higher altitude (lower resolution) would yield quality orthophotos but then the details I wanted to see like potholes and standing water were not clear enough. My point is I think these tools can work really well when the conditions are right, as evidenced by all of the high quality samples and demos, but there are still a lot of situations where you’re just not going to get very high quality due to conditions of the subject area.

[unbearded]

I would say the quality is relative to your input and to what type of application you need results for.

If you are gonna use the pointcloud as a cheaper and faster alternative to LIDAR and need to take measures with centimeter precision, you will need a lot of overlap (we use 75%) and the drone to take the photos automatically to be sure it covers most of the desired area. I would also recommend a commercial tool for the task. We have jobs that take one week to process with state of the art hardware.

But if you just want to do it for fun, you won't need to get this complicated and can do even with your phone.