Updated the README.md with the new workflow for creating additional t…

…ool bit shapes.

src/Mod/Path/Tools/README.md

@@ -1,17 +1,17 @@
 # Tools
 
-Each tool is stored as a JSON file which has the template's path and values for all named constraints of the template.
+Each tool is stored as a JSON file which has the shape's path and values for all attributes of the shape.
 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).
+When a tool is instantiated in a job the PDN body is created from the shape and the attributes and 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
 
@@ -55,33 +55,34 @@ TechDraw's templates.
 ## How to create a new tool
 
 1. Set the tool's Label, this will show up in the object tree
-1. Select a tool shape from the existing templates. If your tool doesn't exist, you'll have to create a new template,
+1. Select a tool shape from the existing shape files. If your tool doesn't exist, you'll have to create a new shape,
    see below for details.
-1. Each template has its own set of parameters, fill them with the tool's values.
+1. Each tool bit shape has its own set of parameters, fill them with the tool's values.
 1. Select additional parameters
 1. 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 describe the bit - for that some
-additional parameters are needed which will be added when an actual bit is parametrized from the template.
+The shape file for a tool bit is expected to contain a PD body which represents the tool as a 3d solid. The PD body
+should be parametric based on a a PropertyBag object so that, when the properties of the PropertyBag are changed the
+solid is updated to the correct representation.
 
 1. Create a new FreeCAD document
 1. Open the `PartDesign` workbench, create a body and give the body a label you want to show up in the bit selection.
-1. 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)
-1. 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`
-1. Any unnamed constraint will not be editable for a specific tool
-1. Once the sketch is fully constrained, close the sketch
-1. Rotate the sketch around the z-axis
+1. Open the Path workbench and (with the PD body selected) create a PropertyBag,
+   menu 'Path' -> 'Utils' -> 'Property Bag'
+   * this creates a PropertyBag object inside the Body (assuming it was selected)
+   * add properties to which define the tool bit's shape and put those into the group 'Shape'
+   * add any other properties to the bag which might be useful for the tool bit
+1. Construct the body of the tool bit and assign experssions referencing properties from the PropertyBag (in the Shape
+   Group) for all constraints.
+   * Position the tip of the tool bit on the origin (0,0)
 1. 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
+   * Whatever you see when saving the document will end up being the visual representation of tool bits with this shape
+
+Not that 'Shape' is the only property group which has special meaning for tool bits. All other property groups are
+copied verbatim to the ToolBit object when one is created.