FreeCAD | Why? & What?

I would like to start updating the `readme` with some information on FreeCAD as this is my current focus.

Proposed initial introductory,`Why?` and `What?` sections.

# Learn CAD/CAM for CNC and laser cutting

We had recently been using Fusion 360 as our parametric modelling tool for laser cutting trials as hobbyists, but in September 2020 [they made some sweeping changes to their personal use license](https://www.autodesk.com/campaigns/fusion-360-personal-use-changes) (see #32), making exporting to `DXF` (a requirement for laser cutting) a paid-for feature.

Our aim is always to _increase accessibility_ and there's no point in providing all of our tutorials and materials open source and then requiring you to pay Autodesk €61/month (at the time of writing) for the software required.

After research into alternatives (see issues), a few options became obvious contenders: Blender, FreeCAD and OpenSCAD.
For _very simple_ 2D geometric designs, [LibreCAD](https://librecad.org/) may also be an interesting option, but not one we have explored in detail.

Whilst Blender is an amazing piece of software when it comes to rendering 3D models and it _is_ possible to [use for laser cutting](https://github.com/dwyl/learn-cad-cam-cnc/issues/33), the lack of [parametric modelling](https://www.designingbuildings.co.uk/wiki/Parametric_modelling#:~:text=Parametric%20modelling%20(or%20parametric%20design,than%20by%20being%20manually%20manipulated.) made it more labour intensive as a transition from Fusion 360.

## FreeCAD | Why?

[FreeCAD](https://www.freecadweb.org/index.php) is a _regularly maintained_, [**open source**](https://github.com/FreeCAD/FreeCAD/) 3D _parametric modelling_ tool, allowing you to fix all the parameters (measurements) of the object you are drawing, with a lot of flexibility between 2D and 3D modelling.

FreeCAD doesn't require any scripting knowledge (unlike OpenSCAD) which makes it more appealing as an accessible solution.

It also has many great features that go beyond our current requirements, but it seems to be a great option for laser cutting needs (as well as for CNC and 3D printing).

## FreeCAD | What?

As a tutorial, it makes a lot more sense to have a set of _video_ tutorials rather than a never-ending text document with many screenshots that are difficult to place within the software itself.
In addition, [FreeCAD's documentation](https://wiki.freecadweb.org/Getting_started) is already pretty good.

But the aim here is to learn FreeCAD _specifically_ for **laser cutting** initially.

This repository therefore contains a subset of resources useful for laser cutting and will not include a _full_ set of tutorials on _all_ of FreeCAD's features.