Step 6: OpenSCAD Manager
########################

Most of the analysis of a design will be done using an :term:`STL` file which
describes a part we create. Before we worry about generating the parts, we can
set up a |PY| class that will manage access to |OSC|_ from the command
line.

Feature 2: Add |OSC|_ Management class
****************************************

The primary purpose of the |OSC|_ manager class is to isolate running
OpenSCAD to perform needed operations. For our first test of this class, we
will launch |OSC|_ and fetch the version of the program we are using.
Unfortunately, getting the |CI| servers to install the version I have on my
machine (installed with Homebrew_) has proven difficult, so we will not test the
actual version, just ensure we get valid output.

The code we need to write will assume that |OSC|_ is on the system path and
can be launched with the name :program:`openscad`.

Test |OSC|_ Version
===================

Users will need to install at least |OSC|_ version 2019.05, so we will set up
a test to check that.

Here is our first test for this class:

..  literalinclude::    ../../tests/test_OpenSCAD.py
    :linenos:
    :caption: tests/test_OpenSCAD.py


And here is the start of our class:

..  literalinclude::    ../../mmdesigner/OpenSCAD.py
    :linenos:
    :lines: 1-13
    :caption: mmdesigner/OpenSCAD.py


With this running locally, we now need to modify the |CI| service control files
and get |OSC| installed on their *virtual machines* for testing. This took some
research, but i finally managed to get things working.

Test OpenSCAD STL Generation
============================

Our next task involves getting |OSC|_ to generate an :term:`STL` file from
the associated :term:`SCAD` file.

..  literalinclude::    ../../mmdesigner/OpenSCAD.py
    :linenos:
    :lines: 14-32
    :caption: mmdesigner/OpenSCAD.py

Mass Property Generator
=======================

Now that we can generate an :term:`STL` file, we can analyze that file to get
the part properties. These will be saved in a :term:`JSON` output file:

..  literalinclude::     ../../mmdesigner/OpenSCAD.py
    :linenos:
    :caption: mmdesigner/OpenSCAD.py

This code depends on **numpy-stl** which needs to be added to the **requirements.txt** file.