Engineering for Ruby

This is a meta-gem for all things related to engineering (particularly CAD stuff). The Engineering module is your one stop shop for all of the tools you need for your latest mad-engineering project.

Activating a dormant volcano? Adding death rays to your secret moon base? Plotting world domination? No problem! There's a gem for that, and you've found it right here.

If your latest and greatest project, and even your older ones, need something that isn't in Engineering, either let me know, or fork and add it yourself (and send me a pull request). Or feel free to create your own gem that reopens the module and adds whatever is missing, if that's more your style.

Dependencies

DXF GitHub RubyGems
Units GitHub
Geometry GitHub RubyGems
Sketch GitHub
Model GitHub

Installation

Engineering has a number of dependencies. Some of which are hosted on RubyGems and can be handled by the gem utility, but others must be installed manually.

The units gem hosted on Rubygems is a bit out-of-date, and generally not the gem we're looking for. So, before installing the engineering gem, we need to manually install the correct units gem.

First, make sure you don't already have a conflicting version of units:

gem uninstall units

Next, clone the gem that we're looking for:

git clone git://github.com/bfoz/units.git

You probably already have rake installed, but if you don't, then do this before going any further:

gem install rake

Finally, install the correct units gem:

cd units && rake install

Now, we can install engineering in the normal fashion:

gem install engineering

And that's it. You're done. Get going with taking over the world already.

Examples

Creating a custom Cube class, the hard way:

require 'engineering'

model :MyCube do
    extrusion 10.cm do
        square 10.cm
    end
end

MyCube.new

Of course, this is ruby, so there's always another way to do it

extrusion :MyCube do
    rectangle Size[10.cm, 10.cm]
end

MyCube.new length:10.cm

Attributes

Models can have attributes that stand-in for values that aren't known until the subclass is instantiated.

model :VariableCube do
    attribute :side_length

    extrusion side_length do
        square side_length
    end
end

Given the above, you can then make cubes of any size you like.

small_cube = VariableCube.new(side_length:1.cm)
large_cube = VariableCube.new(side_length:1.km)

You can also give the attributes values right away, and then use them as properties when defining other geometry.

model :SugarCube do
    attribute side_length: 1.cm

    extrusion side_length do
       square side_length
    end
end

# Stack the cubes
bottom_cube = SugarCube.new
top_cube = SugarCube.new(origin:[0,0,SugarCube.side_length])

Exporting

Once a Model has been defined, it can be instantiated and exported to SketchUp with a single line

SketchUp.write('MyCube.su', MyCube.new)

Then, launch SketchUp, open the Ruby Console (it's in the Window menu), and load 'MyCube.su'. Your new geometry will replace whatever was already in the SketchUp document (a person if you just opened it), so be careful.

engineering