Draft PathArray/pl

Description
The tool places copies of a selected shape along a selected path, which can be a Draft Wire, a Draft BSpline, and similar edges.

The PathArray tool can be used on any object that has a Part TopoShape, meaning 2D shapes created with the Draft Workbench, but also 3D solids created with other workbenches, for example, Part, PartDesign, or Arch.


 * To create orthogonal, polar or circular arrays, use the corresponding, , or tools.
 * To position App Link copies along a path use.
 * To position copies at specified points use or.
 * To create copies and manually place them use or.
 * To create exact copies and manually place or scale them, use or.



Usage

 * 1) Select the object that you wish to distribute.
 * 2) Select the path object or edges along which the object will be distributed.
 * 3) Press the  button.
 * 4) The Array object is immediately created. You must change the properties of the array to change the number and direction of copies created.

Each element in the array is an exact clone of the original object, but the entire array is considered a single unit in terms of properties and appearance.

if the object doesn't seem to be positioned correctly in the path, check that its  is in the origin. Certain objects can be placed anywhere in the 3D space when used with the tool, but others must be at the origin, particularly those created by using  with a 2D profile like a.

Options
There are no options for this tool. Either it works with the selected objects or not.

Properties
A PathArray is derived from a Part Feature ( class), therefore it shares all the latter's properties. In addition to the properties described in Part Feature, the PathArray has the following properties in the property editor.


 * : if it is the copies will be aligned to the path; otherwise they are left in their default orientation.
 * in certain cases the shape will appear flat, in reality it may have moved in the 3D space, so instead of using a flat view, change the view to axonometric.


 * : three modes,, ,.
 * : additional displacement vector that will be applied to each copy along the path. This is useful to make small adjustments in the position of the copies, for example, when its reference point doesn't match the center point of its shape.
 * : if it is, the value of will be used as the local Z direction, when  is  or.
 * : it defaults to ; alignment unit vector that will be used when is.
 * : it defaults to ; unit vector of the local Z direction that will be used when is.


 * : specifies the object to duplicate in the path.
 * : specifies the number of copies to create in the path.
 * : specifies the object along which the copies will be distributed. It must contain in its Part TopoShape; for example, it could be a  or.
 * : specifies the sub-elements (edges) of the on which the copies will be created. The copies will be created only on these edges. If this property is empty, the copies will be distributed on the entire.

Scripting
See also: Autogenerated API documentation and FreeCAD Scripting Basics.

The PathArray tool can be used in macros and from the Python console by using the following function:

Older call:

New call:


 * Creates a object from the, by placing as many as  copies along.
 * Instead of a reference to an object, and  can also be  (strings) of objects existing in the current document.
 * If is given, it is a vector that displaces each of the individual copies by a small amount.
 * If is given, it is a list of edges of, for example, ; the copies will be created along this shorter path.
 * If is, the copies are aligned along the  depending on the value of , which may be ,  or.
 * If is given, it is a unit vector that defines the local tangent direction of the copy along the path. It is used when  is.
 * If is, the value of  is used to determine the local Z direction of the copy along the path. It is used when  is  or.
 * If is, the type of array created will be a PathLinkArray, whose elements are App Link instances instead of simple copies.

Example:

Technical explanation for the Align property
When is, the placement of the copied shapes is easy to understand; they are just moved to a different position in their original orientation.



When is, the positioning of the shapes becomes a bit more complex:
 * 1) First, Frenet coordinate systems are built on the path: X is tangent, Z is normal, Y is binormal.
 * 2) Then the original object is copied to every on-path coordinate system, so that the global origin is matched with the on-path coordinate system origin.



The following images show how the array is produced, depending on which plane the path is.

Path on XY Plane:



Path on XZ Plane:



Path on YZ Plane:



As you reorient the path but not the object, the result is consistent: the object remains aligned to the path the way it was before reorienting the path.

thank you to user DeepSOIC for this explanation.

Additional alignment modes and options introduced in v0.19
Original mode (the default) is the historic alignment mode as in version 0.18. It is not really the Frenet alignment. Original mode uses the normal parameter from Draft.getNormal (or the default) as a constant - it does not calculate curve normal. X follows the curve tangent, Y is the normal parameter, Z is X.Cross(Y).

Tangent mode is similar to Original, but includes a rotation to align the Base object's X to the TangentVector before placing copies. After the rotation, Tangent behaves the same as Original. In previous versions this rotation would be performed manually before invoking PathArray.

Frenet mode orients the copies to a coordinate system along the path. X is tangent to curve, Y is curve normal, Z is curve binormal. If a normal can not be computed (ex a straight line), the default is used.

The ForceVertical option applies to Original and Tangent modes. When this option is applied, the normal parameter from Draft.getNormal is ignored. X follows the curve tangent, Z is the VerticalVector property and Y is X.Cross(Z).

Version 18 cycle chain - Original mode

Railway cross ties (sleepers) - Tangent mode + ForceVertical

Frenet Mode