Each tool is stored as a JSON file which has the template's path and values for all named constraints of the template. It also includes all additional parameters and their values.

Storing a tool as a JSON file sounds great but eliminates the option of an accurate thumbnail. On the other hand, storing each tool as a *.fcstd file requires more space and does not allow for generating tools. If one has an extensive tool aresenal they might want to script the generation of tools which is easily done for a *.json file but practically impossible for *.fcstd files.

When a tool is instantiated in a job the PDN body is created from the template and the constraints are set according to the values from the JSON file. All additional parameters are created as properties on the object. This provides the the correct shape and dimensions which can be used to generate a point cloud or mesh for advanced algorithms (and potentially simulation).

Tool Libraries

Due to each tool being stored in its own file and the storage/organization of those files being quite flexible the importance of a tool library for organisational purposes is quite diminished. The user is free to organise their tools in whichever directory hierarchy they see fit and can also name them as best fits their use and organisation. A tool library is nevertheless a great representation for a physical grouping of tools, such as in an automatic tool changer.

A tool library is a (JSON) file with a mapping of tool id to the path of the tool file. As a consequence each tool can be in multiple libraries and doesn't have an id of it's own. The id is a property of the library.

If a tool from a tool library (or an entire tool library) is added to a job it retains its id from the library as a property. Adding a tool bit directly rsults in the tool getting the next free id assigned.

Tool Controllers

They largely stay the same as they are today. As an additional feature it should be possible to copy a TC, which allows for easy feed/speed changes for the same tool.

Above requirement highlights one change though, that the id should be a property of the Bit, and not of the TC. There are two requirements that are currently mapped to a single id. There needs to be an identification of which TC is being used by a certain op, and which tool number to use for a M6 command.

Paths and Extensibility

The following directory structure is used for supplied (shipped with FreeCAD) tools:

  Tools
    + Bit
    + Library
    + Shape

Strictly speaking a user is free to store their tools wherever they want and however they want. By default the file dialog will open the corresponding directory (depending on context), or whichever directory the user opened last.

Above directory structure with the most common default tools shipped with FreeCAD should be installed analogous to TechDraw's templates.

How to create a new tool

Set the tool's Label, this will show up in the object tree
Select a tool shape from the existing templates. If your tool doesn't exist, you'll have to create a new template, see below for details.
Each template has its own set of parameters, fill them with the tool's values.
Select additional parameters
Save the tool under path/file that makes sense to you

How to create a new tool bit Shape

A tool bit template represents the physical shape of a tool. It does not completely desribe the bit - for that some additional parameters are needed which will be added when an actual bit is parametrized from the template.

Create a new FreeCAD document
Open the PartDesign workbench, create a body and give the body a label you want to show up in the bit selection.
Create a sketch in the XZ plane and draw half the profile of the bit.
- Put the top center of the bit on the origin (0,0)
For any constraint serving as a parameter for the tool (like overall Length) create a named constraint
- The name is the label of the input field
- Names are split at CamelCase boundaries into words in the edit dialog
- Use a ; in the name to add help text which will show up as the entry fields tool tip
- If the tool is used by legacy ops it should at least have one constraint called Diameter
- Use construction lines for constraints that are not directly accessible, like Diameter and Angle
Any unnamed constraint will not be editable for a specific tool
Once the sketch is fully constrained, close the sketch
Rotate the sketch around the z-axis
Save the document as a new file in the Shape directory
- Before saving the document make sure you have Save Thumbnail selected, and Add program logo deselected in FreeCAD's preferences.
- Also make sure to switch to Front View and Fit content to screen
- Whatever you see when saving the document will end up being the visual representation of the template