Ask HN: Why did consumer 3D printing take so long to be invented?

If you think of it as functional/decorative categorisation first of all, obviously some people will overlap but broadly speaking I think people are interested for one or the other, then within the 'decorative' camp you can go a hell of a lot further without and I think it's more obviously reasonable to not care about designing your own models. You never wanted to design your own toys, but there's appeal in printing things not available on Amazon, unofficial merch for a film you like, or whatever.

Not to say there isn't functional stuff (which I exclusively print) on these sites, but often it won't be quite what I want, so yeah I end up in Fusion. (And typically starting from scratch eventually, because for some reason people don't share source, and working with imported STLs is hellish.)

The patents expiring was a big deal, since the main patent was on the fused deposition process itself.

The other factor was that normal desktop computers had become powerful enough to run sophisticated 3d modeling programs and make machine motion computations from 3d design files.

People have been doing CAD/CAM since the 01950s. Boeing started using CNC in 01958 on IBM 704s, and MIT's Servomechanisms Lab (working with the Aircraft Industries Association: https://web.archive.org/web/20090226211027/http://ied.unipr....) sent out CNC ashtrays to newspaper reporters in 01959: https://en.wikipedia.org/wiki/History_of_numerical_control#C.... Pierre Bézier started writing UNISURF in 01968 at Renault, who was using it to design car bodies by 01975. The Utah Teapot was created in 01975, and it consists of nine Bézier patches; you could print the whole dataset on a business card: https://web.archive.org/web/20141120132346/http://www.sjbake...

The IBM 704 was a vacuum-tube machine that could carry out 12000 floating-point additions per second and had a failure about once every 8 hours https://en.wikipedia.org/wiki/IBM_704. The Intel 8008 (not 8088, not 8080, 8008) that came out in 01972 could carry out over 79000 8-bit integer additions per second, which is about the same speed. But much faster computers were already available, such as the PDP-8, in wide use for real-time control, and they very rapidly became much cheaper. Any computation MIT's Servomechanisms Lab could do in the 50s was doable by hobbyists by the 80s.

The reason 3-D printers mostly use stepper motors is that they don't require closed-loop feedback control. 2-D printers from the 01970s used stepper motors for the same reason. They were accessible to hobbyists; in the 80s I had a Heathkit printer someone had built from a kit in the 70s.

If you wanted to print Frank Sinatra's face on a toilet, I think you'd probably want at least a 64×64 heightfield to get a recognizable Sinatra; 256×256 would be better than the line-printer pictures we were doing. 8 bits per heightfield point would be 65 kilobytes, which would fit on the floppy disks we were using at the time. This would have been totally feasible, though digitizing Frank Sinatra would have been a nontrivial project, quite aside from printing him.

So I don't think computation was the limiting factor.

Your "basically banging into the object with a very crude sensor, so there's no generation of geometry at all" is called a "pantograph" and it has been a common way to copy three-dimensional objects and engrave letters with a milling machine for 180 years: https://en.wikipedia.org/wiki/Pantograph#Sculpture_and_minti...

A 10MB hard drive cost $3,000-4,000 in 1980.

That's $12k-15k today.

Just opening the .stl file and having it render (USABLY) on screen in high-resolution was probably not economical until the late 1990s-early 2000s.

I am used to computing tasks being human-perception instant. It takes tens of seconds to run repairs on 3d models, which means it would have taken tens of hours to do that same thing, if there was even enough RAM, in the 90s.