MakeBlock Parametric Straight Bracket

This is a parametric bracket generator for MakeBlock which can generate parts of various sizes. All MakeBlock structural parts use M4 screws with the holes separated by an 8mm pitch, so I created this generator to generate flat parts with a specified number of holes in the x and y directions (as well as the part thickness). Most printers close inner holes up a bit, so a 2mm radius will create a part where the M4 screws "bite", and 2.4mm radius will create one where they're loose and need a nut.

You can also create longer openings within the part (such as I did in the 3x9 part) by adding the "open" row or column to the appropriate "open_" array, starting at column/row zero. For example, to make a 3x3 part with a cross in it, put 1 in the open_xs and 1 in the open_ys with rows=3 and columns=3. For multiple rows or column, separate with commas, (eg. 0,1,2). Note that you can create islands with this feature, so be careful.

[MakeBlock](http://www.makeblock.cc) is a hobby robotic