Feature Placement
Placement feature represent a single Placement object. There are actually 4 different features involved, with different functionality.
- Feature Placement - placement is specified by Placement property, in the manner FreeCAD provides.
- Feature PlacementAx - placement is constructed from axes directions specified as vectors
- Feature PlacementEuler - has Euler angles available as properties.
- Feature ArrayFromShape - for making placements derived from shapes, or linked to Placement properties of objects.
This feature represents a free-standing Placement, that can be moved by all means FreeCAD provides (e.g., by Edit->Placement, or by modifying Placement propety, or by using Draft Move/Rotate)
Set to true to flip placement's Z local axis direction. Placement's Y axis is also reversed, X axis is preserved. (One can only flip two axes at a time, to preserve axis system handedness)
If PlacementChoice is Custom, setting the property to true will flip Z axis, and the property will self-reset back to false, to avoid flipping the placement on every recompute. If PlacementChoice is not Custom, the property will not self-reset.
Set to true to invert the placement (inverse placement is the placement that undoes the original placement).
If PlacementChoice is Custom, setting the property to true will invert the placement, and the property will self-reset back to false, to avoid inverting the placement on every recompute. If PlacementChoice is not Custom, the property will not self-reset.
This property acts like offset value in sketch orientation dialog. This property is only active if PlacementChoice is not Custom.
This property lets one to choose a standard placement. Available options are:
- Custom. This unlocks the placement, and allows directly manipulating it by editing Placement property. This also makes the Placement object moveable with all kinds of moving tools, Draft Move for example.
- XY Plane. X axis along global X axis; Y axis along global Y axis, Z axis along global Z axis (assuming FlipZ and Invert are False). This placement is a trivial placement, or zero placement: its local coordinate system is coincident with global; applying this placement does nothing.
- XZ Plane. X axis along global X axis; Y axis along global Z axis, Z axis opposite to global Y axis (assuming FlipZ and Invert are False).
- YZ Plane. X axis along global Y axis; Y axis along global Z axis, Z axis along global X axis (assuming FlipZ and Invert are False).
(click the title)
Constructs a placement, by aligning local axes with directions supplied as vectors (properties 'XDir_wanted', 'YDir_wanted', 'ZDir_wanted'). For the local origin of the placement, 'Position' (aka 'Base') property of 'Placement' property is used.
'Priority' property controls, which directions are to be considered more important to follow than others.
Axis system of a placement is a rather constrained thing, so it can't be made to follow three arbitrary axis directions at once. The axis system must be orthogonal (i.e., all axes must be perpendicular to each other), and right-handed.
Priority can take the values of form XYZ, where the letters appear in different order. XYZ priority means that local X axis direction is followed strictly to match 'XDir_wanted'; local Y direction is made to be as close as possible to YDir_wanted, and Z axis is computed from the rest and ZDir_wanted is completely ignored.
Vectors that secify the desired directions of corresponding axes of the placement. The way they are followed is affected by 'Priority' property.
These properties display the actual directions of axes of the computed placement.
Constructs a placement with given Euler angles (yaw, pitch, roll). For the local origin of the placement, 'Position' (aka 'Base') property of 'Placement' property is used.
Angle of rotation around global Z axis. This angle corresponds to direction of plane's flight in XY plane.
Angle of rotation around intermediate (semi-local) Y axis. This angle corresponds to plane's angle of attack.
Angle of rotation around local X axis. This angle corresponds to plane tilting sideways.
There are 12 commands under a drop-down toolbar button. Their titles are mostly self-explanatory. Note that the commands don't cover all posible ways one can preset the placement - some placements can only be achieved by choosing the closest preset, and then editing properties manually.
The last four commands create a different feature - ArrayFromShape - preset to make a single placement out of selected object. See Feature ArrayFromShape for info on setting up the feature after creating it.