2x1 Adjustable Lego-like Brick

Simple 2x1 Lego-like brick.

Note: my customizable brick generator is now available (https://www.thingiverse.com/thing:3424550)!

This is my first attempt to create a Customizer thing. The customizer allows you to set your own "gap factor", which is an amount by which the brick size will be reduced, in order to help you improve fitting with other bricks.

##Background

Lego bricks are notoriously difficult to print well.

Every printer is different. Within a printer, different materials may behave differently. Within a material, different vendors or even different spools from the same vendor may behave differently. If all that is constant, different slicers (or different settings in the slicer, perhaps from different people) can create different results. Even if none of that changes, a bed level might vary slightly causing subtly different results for the same part.

Despite all this, a given print will generally be consistent within itself, and it will match the design of the source mesh/model very closely... but not perfectly. Lego bricks, though, do need an extremely precise match to the source model in order to fit well.

##Goal

While a simple 2x1 brick isn't much in itself, this is meant as the first step of a larger project intended to create Lego-like brick models that actually print well and also fit with other Lego parts, regardless of how your specific printer/filament/slicer behave.

The goal is to have all the basic bricks represented as one Customizer scad, where you simply pick the width and breadth in terms of number of studs (say, 2 by 4), the style of piece (brick, plate, or base, where a base is a plate with a solid bottom), and the "gap factor" needed for your printer, and you'll get an stl file that should fit properly with other bricks.

Additionally, a calibration stl will be provided with a series of 2x2 Lego bricks pre-rendered at certain gaps, with the gap number embossed on a side. You can print the calibration bricks and test them against real Lego bricks to find out what works best for your printer right now, and based on the results know what gap factor you need to use with the Customizer.

Finally, the plan is to deviate from a standard Lego brick in ways that improve printing outcomes. For example, real Lego bricks have a small hole underneath the stud. I've found a brick prints better if that hole is not there; a solid piece here helps bridge the span needed for the first couple of layers when printing the top. I'm also considering some archways on the inside of the brick for the same reason.

All this is still to come, if I ever get the time. This is just the first 2x1 brick... and not even a complete brick at that; it still needs the center post. The purpose here is to give me a basic feel for OpenSCAD and the Customizer. Also, it makes an early part available, so people can try out different gap factors now. Speaking of, I appreciate feedback from people trying different gaps and how it helps (or not), in order to eventually set a meaningful default value here.

##Disclaimers

At this time, I'm using a "No Derivatives" license. I appreciate people honoring this for the time being. I intend to use a more-permissive license once the project get's a little further along.

Lego is trademark The LEGO Group