If you enjoy this, you might also enjoy the Smithsonian's 3D image library, with models you can download and print:

http://3d.si.edu/

I'm curious if 3D scanners are cheaper/portable/widely available now ?

The cheapest way is possibly to take a lot of photos and create a 3D model using this program: http://ccwu.me/vsfm/

It requires a lot of RAM though (on the order of 16 GB for most scenes).

I've used a program called PhotoModeler [1] at work, which does the same thing.

You use a consumer camera + a calibration chart to get the specifics about the lens setup on the camera, and then just take a whole heap of photos around the object in question. You add the photos to the program and it asks you to identify common points. This puts them all in 3d perspective and you set a dimension on a known length to scale it.

For mapping large-scale machinery (train stuff) I've managed to get a ~5mm accuracy out of it. That's great when you don't have drawings.

[1]: http://www.photomodeler.com/index.html

That would be really cool to play around with. Do you know if it does interiors as well? It doesn't look like it from the website.

You could upload it to https://photosynth.net/preview if you just want to play around. It doesn't require you to have a lot of RAM, but you can only view it on the Photosynth website and you can't really tweak anything.

I've recently had some luck using an old Microsoft Kinect and their free library of scanning software:

https://www.microsoft.com/en-us/kinectforwindows/

You can get a Kinect V1 on ebay for less than $30, but you need a graphics card that fully supports DirectX 11 and a somewhat powerful machine to scan objects. Unfortunately, you can't scan small objects because the Kinect goes blind a less than a meter, but I have been able to scan people and print out recognizable busts of them. I don't know if the Kinect V2 is any better.

Cubify has a portable handheld 3D scanner that looks like it might work well, but I can't afford the $400 to try it out:

http://cubify.com/en/products/sense

Kinect V1 under Windows doesn't need DirectX 11. Only the Kinect V2 with official drivers does. There are OpenGL and CPU implementations for the V2 if you go with open source drivers.

They have a very high resolution model of Michaelangelo's "David", with over a billion polygons, but it takes special permission to get the data. They don't want people stamping out copies.

Why would they care if you made an exact copy of Michaelangelo's David? I imagine that if I had the actual Declaration of Independence on display, I'd be flocked with visitors, but if I had an exact copy, indistinguishable to the human eye, no one would bother to look at it.

Maybe that's their reasoning, but if so it seems a bit overblown.

What "original" means in the art world is amusing. It's all about monetization.[1]

Cranking out a copy of Michaelangelo's David as a bronze would be a nice project. Hypermill/Daishin should take that on. Each year they do some insanely elaborate piece of art in metal as a CNC machining demo.[2]

[1] http://www.artnews.com/2013/06/05/the-degas-debate/ [2] https://www.youtube.com/watch?v=RnIvhlKT7SY

Until you claim that your (indistinguishable) copy is the real thing, at which point theirs is ruined.

I'm wondering what accuracy one can achieve with structure from motion and flickr as it was done in this project: http://grail.cs.washington.edu/rome/

A bit of context: these models are used in countless of computer graphics publications. Try a image search for "Stanford Bunny" for example.