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Ask HN: How to produce a 3D scan of a car from a mobile phone?

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21–27 of 27 posts

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#21
The Einstar Vega goes for $1,799 USD, which is about 2x the price of a standalone iPhone. The scans will be better than anything you can get using a mobile phone (though it's essentially just that?). Lots of videos on YT comparing the Vega and OG Einstar, especially for automobile scanning.

The downsides of the Vega I mostly didn't see mentioned on YT:

- Required an account to use

- Required WIFI to setup (don't need WIFI past that except when updating)

- Required an app to get scan files off it, but will work for your OBJ use case

Battery life has been a few scans. Do the processing later and get the scans up front.

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#22
I've had a lot of success scanning engines, engine bays, and crossmembers with Scandy Pro on my iPhone 15 Pro. It's slow going, you really need to be patient and methodical to get a good scan. I often make multiple scans and combine them into a single model on my computer.

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#23

That’s going to depend a whole lot on their budget, your capabilities, and the final requirements — is this being used for visuals, or metrology? I have suggestions for getting visual fidelity but if you’re looking for an explicit 3D model maybe that’s not what you’re going for. (There are new approaches like NeRFs and Gaussian splats that don’t use traditional 3D formats, but look truly great.)

FYI, my colleagues in the past have used Metashape, if you're in the market for an OTS solution. There is also Epic's RealityCapture; I have not used either one, but as far as I can tell capture density and quality matter a lot. For any solve, get good light (outdoors preferred mostly for intensity), and shoot a lot of coverage. If you can use a DSLR (competently) that might help, though today's mobile phones are quite good. If using an iPhone, shoot RAW (Android may have something equivalent?) -- small scale compression artifacts contribute noise to the solve.

And good luck, whatever direction you take this!

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#24
Openmvs: https://github.com/cdcseacave/openMVS

^ uses OpenMVG: https://github.com/openMVG/openMVG

Colmap: https://github.com/colmap/colmap

Opensfm: https://github.com/mapillary/OpenSfM

Meshlab: https://www.meshlab.net/ (open source)

I also hear meshroom is popular but I haven't used it.

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#25
post #21

The Einstar Vega goes for $1,799 USD, which is about 2x the price of a standalone iPhone. The scans will be better than anything you can get using a mobile phone (though it's essentially just that?). Lots of videos on YT comparing the Vega and OG Einstar, especially for automobile scanning. The downsides of the Vega I mostly didn't see mentioned on YT: - Required an account to use - Required WIFI to setup (don't need…

The other thing is you'll need markers. At least in my experience. I think if you don't need precision photogrammetry and AI will get you the results way faster

(To be clear I love my Vega. Game changer. Just a bit heavy handed if you're not making car body parts)

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#26
The main issue isn’t software or the phone in this case. It’s the task itself. Photogrammetry is one of the worst options to scan a car. Let me answer why:

Photogrammetry relies on unique points on an object. Imagine that the software doesn’t have any information besides what’s visible on the photos. Basically it tries to match the same points on different photos and is then able to reconstruct the object by estimation.

This works great for objects which got a unique texture or many unique points. Like a newspaper, which has a lot of non-repeating text and thus a non-repeating texture. This doesn’t word great for single color objects, as the software can’t distinguish different points on the object.

This does also work on matte,opaque objects, as reflections will show the surroundings and may alter the color.

Now combine the above: cars are usually single color, shiny and have very little corners and edges. This is photogrammetries worst nightmare. Even if you coat the whole car in a single even layer of something, then it’s still single color…

What works (but it’s a painful task!) is to sprinkle colored matte dots onto the car, preferably in a random pattern. Then you take houndreds of photos of the car. It’ll take a long time and it must be done in an even lit place. So no direct sunlight but a cloudy day or inside a building with a lot of indirect lighting.

In short: Don’t try it and buy a scanner like Einstar instead. Renting a more expensive scanner is also an option. You’ll still need to coat the car, but it’s faster and less painful.

Re: Ask HN: How to produce a 3D scan of a car from a mobile phone?

#27
post #21

The Einstar Vega goes for $1,799 USD, which is about 2x the price of a standalone iPhone. The scans will be better than anything you can get using a mobile phone (though it's essentially just that?). Lots of videos on YT comparing the Vega and OG Einstar, especially for automobile scanning. The downsides of the Vega I mostly didn't see mentioned on YT: - Required an account to use - Required WIFI to setup (don't need…

The other thing is you'll need markers. At least in my experience. I think if you don't need precision photogrammetry and AI will get you the results way faster (To be clear I love my Vega. Game changer. Just a bit heavy handed if you're not making car body parts)

100%. Lots of things work as markers, too! I ended up substituting markers for taped-on construction paper when scanning stainless steel surfaces with curves, the tape serving as feature for the scanner to pickup...worked well enough :)
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