Last time I gave a theoretical introduction to 3D printers and talked briefly about some concepts such as self replication and the effect such devices would have on society. Today I'd like to show you two specific projects that can built for more or less $1,000, both of which are fully functional 3D-plastic printers, and both of which are open-sourced and actively being developed.

Make no mistake, these are set to be the next big thing and will change the world as we know it. I'll also briefly cover a site where you can download models to make once you've built your 3D printer!

MakerBot

MakerBot is the first well-publicised DIY 3D printer and as such has had a good amount of time to mature. Last week, they even raised $10 million in Venture Capital, so you can be damn sure this one is on the right track.

To give you an overview of the machine better than I could ever hope to explain it in text, here's the Make-man himself Bre Pettis talking about the MakerBot.

Note: The latest version is the Thing-O-Matic, but the model seen in the video is the "Cupcake CNC 3D Printer".

The Thing-O-Matic (seen below) is also now able to continuously print objects by "ejecting" them once finished. So that actually means you can have your own private factory line. Above all, just look at it - it's so incredibly cute, wouldn't you want one in your workshop?

As for self-replication, the MakerBot is somewhat limited by its build area (the physical dimensions of the largest object that can be printed) of 10cm, but one enterprising young fellow achieved it by gluing many of the parts together. Those looking for a larger build area should look no further than the RepRap.

RepRap

The RepRap is a more DIY effort that has a larger build area of 20cm, but requires a lot more tweaking and calibration. It's also not quite as cute, but easier to repair and upgrade - apparently - and users claim you will learn a lot more in the process of building one.

While you can purchase the complete ready-made kit from BitsFromBytes for between £800-£1,200, the RepRaps are designed from the ground up to be self-replicating at a current rate of 50%. That means each RepRap can make 50% of the parts required to make another RepRap, which is quite mind blowing.

This was first achieved back in 2008. Future versions of the RepRap printer will of course be able to be printed by the current version(!), and hopes to raise the percentage of self-replicability even further.

Thingiverse

From the Make-crew, the Thingiverse is a community open-source repository for digital 3D object designs, as well as a social network for people who actually design or make them. Some of the things you can download and print on your own 3D printer understandably range from the absolutely ridiculous - a Mentos Diet Coke cannon; insanely awesome - a life-size replica of the Thundercats Sword of Omens; to the frankly quite useful - drawer dividers. You can find them all in the "popular" archives.

Really though, it's perhaps time to stand back, take a breath, and just try to comprehend how unbelievably cool this all is - you can download and print a physical object. This, dear readers, is the future - but it's also here right now. Learn more about 3D printing by reading our complete beginner's guide to 3D printing.

Let us know in the comments if you think this is the most awesome thing since sliced bread, or if you're planning to build one for yourself! We'd love some pictures even if you have built one. Or what would you print on yours?