Draft PathArray: Difference between revisions

From FreeCAD Documentation
m (Creates)
m (plural)
Line 37: Line 37:


<!--T:7-->
<!--T:7-->
There are no options for this tool. Either it works with the selected object or not.
There are no options for this tool. Either it works with the selected objects or not.


==Properties== <!--T:8-->
==Properties== <!--T:8-->

Revision as of 00:15, 16 November 2018

Draft PathArray

Menu location
Draft → PathArray
Workbenches
Draft, Arch
Default shortcut
None
Introduced in version
0.14
See also
Draft Array, Draft PointArray

Description

The PathArray 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 2D shapes created with the Draft Workbench, but can also be used on many types of 3D objects such as those created with the Part, PartDesign, or Arch Workbenches.

To position copies in an orthogonal array use Draft Array; to position copies at specified points use Draft PointArray; to create copies or clones, and manually place them use Draft Move, Draft Rotate, and Draft Clone.

How to use

  1. Select an object which you wish to distribute.
  2. Select a path object or some edges along which the object will be distributed.
  3. Press the Draft PathArray button.

The base object should be centred around the origin, even if the path starts somewhere else.

The count, alignment, and position of the copies along the path can be changed after creation by changing its properties.

Options

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

Properties

  • DataBase: specifies the object to duplicate in the path.
  • DataPathObj: specifies the path object.
  • DataPathSubs: specifies the sub-elements (edges) of the path object. This property does not yet appear in the property editor.
  • DataCount: specifies the number of copies of the base object.
  • DataAlign: if it is true the copies are aligned to the path; otherwise they are left in their default orientation.
Note: 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.
  • DataXlate: specifies a translation vector (x, y, z) to displace each copy along the path.
Note: when DataAlign is true, the vector is relative to the local tangent, normal or binormal coordinates; otherwise the vector is relative to the global coordinates.

Scripting

See also: Draft API and FreeCAD Scripting Basics.

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

PathArray = makePathArray(baseobject, pathobject, count, xlate=None, align=False, pathobjsubs=[])
  • Creates a PathArray object from the baseobject, by placing as many as count copies along pathobject.
    • If pathobjsubs is given, it is a list of sub-objects of pathobject, and the copies are created along this shorter path.
  • If xlate is given, it is a FreeCAD.Vector that indicates an additional displacement to move the base point of the copies.
  • If align is True the copies are aligned to the tangent, normal or binormal of the pathobject at the point where the copy is placed.

Example:

import FreeCAD,Draft

p1 = FreeCAD.Vector(500, -1000, 0)
p2 = FreeCAD.Vector(1500, 1000, 0)
p3 = FreeCAD.Vector(3000, 500, 0)
p4 = FreeCAD.Vector(4500, 100, 0)
spline = Draft.makeBSpline([p1, p2, p3, p4])
object = Draft.makePolygon(3, 500)

PathArray = Draft.makePathArray(object, spline, 6)

Technical explanation for the Align property

When DataAlign is false, the placement of the copied shapes is easy to understand; they are just moved to a different position in their original orientation.

Align false
Align false

When DataAlign is true, 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:

XY Plane
XY Plane

Path on XZ Plane:

XZ Plane
XZ Plane

Path on YZ Plane:

YZ Plane
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.

Editor: thank you to user DeepSOIC for this explanation.