Std Placement

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Std Placement

Menu location
Edit → Placement...
Workbenches
All
Default shortcut
None
Introduced in version
-
See also
Std Alignment, Placement

Description

The Std Placement command displays the Placement task panel for a selected object.

The Placement task panel

Usage

  1. Select a single object that has a DataPlacement property.
  2. Select the Edit → Placement... option from the menu.
  3. Change one or more of the translation and rotation parameters.
  4. Do one of the following:
    • Press the OK button to apply the changes and close the task panel.
    • Press the Apply button to apply the changes, but keep the task panel open for further changes.
  5. Press Esc or the Cancel button to abort the operation. This will undo any changes that have not been applied.

The dialog can also be launched by clicking on the ellipsis button ... that appears in the Property editor when you click on the DataPlacement property.

Notes

  • For more information about the placement parameters see the Placement page, and the Aeroplane tutorial.
  • The rotation angle can be set in degrees in the GUI but is stored in radians internally so that angles usually have to be converted when used in scripts.

Scripting

See also: Autogenerated API documentation and FreeCAD Scripting Basics.

See the Python scripting tutorial.

A placement is internally defined by a matrix; in many cases it is simpler to represent it by means of two components, a Base point (vector), and a Rotation value. The Rotation itself has different representations; it can be entirely defined by the value of a "quaternion" (xi + yj + zk + w), but it can also be described by a rotation Axis (unit vector) and a rotation Angle (radians). 

import FreeCAD as App

doc = App.newDocument()
obj = doc.addObject("Part::Cylinder", "Cylinder")

print(obj.Placement)
# Placement [Pos=(0,0,0), Yaw-Pitch-Roll=(0,0,0)]
print(obj.Placement.Base)
# Vector (0.0, 0.0, 0.0)
print(obj.Placement.Rotation)
# Rotation (0.0, 0.0, 0.0, 1.0)

print(obj.Placement.Rotation.Angle)
# 0.0
print(obj.Placement.Rotation.Axis)
# Vector (0.0, 0.0, 1.0)
print(obj.Placement.Rotation.Q)
# (0.0, 0.0, 0.0, 1.0)

Move the base point of the object, then rotate the object 45 degrees around the X axis.

The math module supplies a method radians() to easily convert degrees to radians and has to be imported at first. 

import math

obj.Placement.Base = App.Vector(5, 3, 1)
obj.Placement.Rotation.Axis = App.Vector(1, 0, 0)
obj.Placement.Rotation.Angle = math.radians(45)

print(obj.Placement)
# Placement [Pos=(5,3,1), Yaw-Pitch-Roll=(0,0,45)]
print(obj.Placement.Rotation.Q)
# (0.3826834323650898, 0.0, 0.0, 0.9238795325112867)
print(obj.Placement.Matrix)
# Matrix ((1,0,0,5),(0,0.707107,-0.707107,3),(0,0.707107,0.707107,1),(0,0,0,1))


Std Base
User documentation
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